Method and Apparatus for Tissue Ablation

ABSTRACT

Methods of ablating endometrial tissue are disclosed. The methods include providing an ablation device that has a catheter with a hollow shaft through which an ablative agent can travel, a first positioning element, and a second positioning element positioned on the catheter distal to the first positioning element. The second positioning element is a disc shaped wire mesh and has a diameter in a range of 0.1 mm to 10 cm.

CROSS-REFERENCE

The present application is a division application of U.S. patentapplication Ser. No. 14/158,687, entitled “Method and Apparatus forTissue Ablation” and filed on Jan. 17, 2014, which relies on U.S.Provisional Patent Application No. 61/753,831, of the same title andfiled on Jan. 17, 2013, for priority.

U.S. patent application Ser. No. 14/158,687 is also acontinuation-in-part of U.S. patent application Ser. No. 13/486,980,entitled “Method and Apparatus for Tissue Ablation” and filed on Jun. 1,2012, which relies on U.S. Provisional Patent Application No.61/493,344, of the same title and filed on Jun. 3, 2011, for priority.

U.S. patent application Ser. No. 13/486,980 is also acontinuation-in-part application of U.S. patent application Ser. No.12/573,939, entitled “Method and Apparatus for Tissue Ablation” andfiled on Oct. 6, 2009, which relies on U.S. Provisional PatentApplication No. 61/102,885, of the same title and filed on Oct. 6, 2008,for priority.

The aforementioned applications are herein incorporated by reference intheir entirety.

FIELD

The present specification relates to medical apparatuses and proceduresused in tissue ablation. More particularly, the present specificationrelates to devices and methods for ablation of tissue in hollow andsolid organs comprising positioning attachments and/or components ormedia capable of conducting an ablative agent.

BACKGROUND

Ablation, as it pertains to the present specification, relates to theremoval or destruction of a body tissue, usually by surgery orintroduction of a noxious substance. Ablation is commonly used toeliminate diseased or unwanted tissues, such as, but not limited to,cysts, polyps, tumors, hemorrhoids, and other similar lesions.

Colon polyps affect almost 25% of the population over the age of 50.While most polyps are detected on colonoscopy and easily removed using asnare, flat sessile polyps are hard to remove using the snare techniqueand carry a high risk of complications, such as bleeding andperforation. Recently, with improvement in imaging techniques, more flatpolyps are being detected. Endoscopically unresectable polyps requiresurgical removal. Most colon cancer arises from colon polyps and, safeand complete resection of these polyps is imperative for the preventionof colon cancer.

Barrett's esophagus is a precancerous condition effecting 10-14% of theUS population with gastro esophageal reflux disease (GERD) and is theproven precursor lesion of esophageal adenocarcinoma, the fastest risingcancer in developed nations. The incidence of the cancer has risen over6 fold in the last 2 decades and the mortality rate has risen by 7 fold.The 5-year mortality rate from esophageal cancer is 85%. Ablation ofBarrett's epithelium has shown to prevent its progression to esophagealcancer.

Benign Prostatic Hyperplasia (BPH) is a non-cancerous condition of theprostate defined by an increase in the number of prostatic stromal andepithelial cells, resulting in an overall increase in the size of theprostate. The increase in size can constrict the prostatic urethra,resulting in urinary problems such as an increase in urinary frequency,urinary hesitancy, urinary retention, dysuria, and an increase in theoccurrence of urinary tract infections (UTI's). Approximately 50% of menshow histological evidence of BPH by age 50, which rises to 75% by age80. About half of these men have symptoms. Although BPH does not lead tocancer, it can have a significant impact on urinary health and qualityof life. Therapies aimed at alleviating the symptoms associated with BPHinclude those involved with reducing prostate size, such astransurethral microwave thermotherapy and transurethral needle ablation,which uses RF energy. When such less invasive therapies are ineffective,surgery, such as transurethral resection of the prostate, often becomesnecessary.

Prostate cancer is diagnosed in approximately 8% of men between the agesof 50 and 70 and tends to occur in men as they grow older. Menexperiencing symptoms with prostate cancer often exhibit symptomssimilar to those encountered with BPH and can also suffer from sexualproblems caused by the disease. Typically, men diagnosed with prostatecancer when the cancer is at an early stage have a very good prognosis.Therapy ranges from active surveillance to surgery and radiation andchemotherapy depending on the severity of the disease and the age of thepatient.

Dysfunctional uterine bleeding (DUB), or menorrhagia, affects 30% ofwomen in reproductive age. The associated symptoms have considerableimpact on a woman's health and quality of life. The condition istypically treated with endometrial ablation or a hysterectomy. The ratesof surgical intervention in these women are high. Almost 30% of women inthe US will undergo hysterectomy by the age of 60, with menorrhagia orDUB being the cause for surgery in 50-70% of these women. Endometrialablation techniques have been FDA approved for women with abnormaluterine bleeding and with intramural fibroids less than 2 cm in size.The presence of submucosal uterine fibroids and a large uterus size havebeen shown to decrease the efficacy of standard endometrial ablation. Ofthe five FDA approved global ablation devices (namely, Thermachoice,hydrothermal ablation, Novasure, Her Option, and microwave ablation(MEA)) only microwave ablation has been approved for use where thesubmucosal fibroids are less than 3 cm in size and are not occluding theendometrial cavity and, additionally, for large uteri up to 14 cm inwidth.

The known ablation treatments for Barrett's esophagus include lasertreatment, ultrasonic ablation, photodynamic therapy (PDT) usingphoto-sensitizer drugs, multipolar electrocoagulation, such as by use ofa bicap probe, argon plasma coagulation (APC), radiofrequency ablation,and cryoablation. The treatments are delivered with the aid of anendoscope wherein devices are passed through the channel of theendoscope or alongside the endoscope.

Conventional techniques have inherent limitations, however, and have notfound widespread clinical applications. First, most of the hand heldablation devices (bicap probe, APC, cryoablation) are point and shootdevices that create small foci of ablation. This ablation mechanism isoperator dependent, cumbersome, and time consuming. Second, because thetarget tissue is moving due to patient movement, respiration movement,normal peristalsis, and vascular pulsations, the depth of ablation ofthe target tissue is inconsistent and results in a non-uniform ablation.Superficial ablation results in incomplete ablation with residualneoplastic tissue left behind. Deeper ablation results in complicationssuch as bleeding, stricture formation, and perforation. All of theselimitations and complications have been reported with conventionaldevices.

For example, radiofrequency ablation uses a rigid bipolar balloon basedelectrode and radiofrequency thermal energy. The thermal energy isdelivered by direct contact of the electrode with the diseased Barrett'sepithelium allowing for a relatively uniform, large area ablation.However, the rigid electrode does not accommodate for variations inesophageal size and is ineffective in ablating esophageal tissue in atortuous esophagus, proximal esophageal lesions as an esophagus narrowstoward the top, and esophageal tissue at the gastroesophageal junctiondue to changes in the esophageal diameter. Nodular disease in Barrett'sesophagus also cannot be treated using the rigid bipolar RF electrode.Due to its size and rigidity, the electrode cannot be passed through thescope. In addition, sticking of sloughed tissue to the electrode impedesdelivery of radiofrequency energy, resulting in incomplete ablation. Theelectrode size is limited to 3 cm, thus requiring repeat applications totreat larger lengths of Barrett's esophagus.

Photodynamic therapy (PDT) is a two part procedure that involvesinjecting a photo-sensitizer that is absorbed and retained by theneoplastic and pre-neoplastic tissue. The tissue is then exposed to aselected wavelength of light which activates the photo-sensitizer andresults in tissue destruction. PDT is associated with complications suchas stricture formation and photo-sensitivity which has limited its useto the most advanced stages of the disease. In addition, patchy uptakeof the photosensitizer results in incomplete ablation and residualneoplastic tissue.

Cryoablation of the esophageal tissues via direct contact with liquidnitrogen has been studied in both animal models and humans and has beenused to treat Barrett's esophagus and early esophageal cancer. A spraycatheter that directly sprays liquid N₂ or CO₂ (cryoablation) or argon(APC) to ablate Barrett's tissue in the esophagus has been described.These techniques suffer the shortcoming of the traditional hand-helddevices. Treatment using this probe is cumbersome and requires operatorcontrol under direct endoscopic visualization. Continuous movement inthe esophagus due to respiration or cardiac or aortic pulsations ormovement causes an uneven distribution of the ablative agent and resultsin non-uniform and/or incomplete ablation. Close or direct contact ofthe catheter to the surface epithelium may cause deeper tissue injury,resulting in perforation, bleeding, or stricture formation. Too distanta placement of the catheter due to esophageal movement will result inincomplete Barrett's epithelium ablation, requiring multiple treatmentsessions or buried lesions with a continued risk of esophageal cancer.Expansion of cryogenic gas in the esophagus results in uncontrolledretching which may result in esophageal tear or perforation requiringcontinued suctioning of cryogen.

Colon polyps are usually resected using snare resection with or withoutthe use of monopolar cautery. Flat polyps or residual polyps after snareresection have been treated with argon plasma coagulation or lasertreatment. Both these treatments have the previously mentionedlimitations. Hence, most large flat polyps undergo surgical resectiondue to the high risk of bleeding, perforation, and residual diseaseusing traditional endoscopic resection or ablation techniques.

Most of the conventional balloon catheters traditionally used for tissueablation either heat or cool the balloon itself or a heating elementsuch as radio frequency (RF) coils mounted on the balloon. This requiresdirect contact of the balloon catheter with the ablated surface. Whenthe balloon catheter is deflated, the epithelium sticks to the catheterand sloughs off, thereby causing bleeding. Blood can interfere with thedelivery of energy, i.e. energy sink. In addition, reapplication ofenergy will result in deeper burn in the area where superficial lininghas sloughed. Further, balloon catheters cannot be employed fortreatment in non-cylindrical organs, such as the uterus or sinuses, andalso do not provide non-circumferential or focal ablation in a holloworgan. Additionally, if used with cryogens as ablative agents, whichexpand exponentially upon being heated, balloon catheters may result ina closed cavity and trap the escape of cryogen, resulting incomplications such as perforations and tears.

Metal stents have been used for palliation of malignant obstruction.However, tumor ingrowth continues to be a significant problem affectingstent longevity. Covered stents provide a good solution for in-growth,however, tumor compression can lead to stent blockage and dysfunction.Traditional coverings on the stents, such as silicone, have poor thermalconductivity and do not allow for successful thermal therapy after thestent has been deployed.

Accordingly, there is a need in the art for improved devices and methodsfor delivering ablative agents to a tissue surface, for providing aconsistent, controlled, and uniform ablation of the target tissue, andfor minimizing the adverse side effects of introducing ablative agentsinto a patient. What is also needed is a stent that provides the abilityto deliver ablative therapy to an inoperable tumor post deployment.

SUMMARY

The present specification is directed toward a device to performablation of endometrial tissue, comprising a catheter having a shaftthrough which an ablative agent can travel, a first positioning elementattached to said catheter shaft at a first position, wherein said firstpositioning element is configured to center said catheter in a center ofa cervix, and an optional second positioning element attached to saidcatheter shaft at a second position, wherein the shaft comprises aplurality of ports through which said ablative agent can be released outof said shaft and wherein said ports are located between said firstposition and second position.

Optionally, the first positioning element is conical. The firstpositioning element comprises an insulated membrane which can beconfigured to prevent an escape of thermal energy through the cervix.The second positioning element is disc shaped. The second positioningelement has a dimension which can be used to determine a uterine cavitysize. The second positioning element has a dimension which can be usedto calculate an amount of thermal energy needed to ablate theendometrial tissue. The device also includes at least one temperaturesensor, which can be used to control delivery of the ablative agent,such as steam.

Optionally, the second positioning element is separated from endometrialtissue to be ablated by a distance of greater than 0.1 mm. The firstpositioning element is a covered wire mesh. The first positioningelement is comprises a circular body with a diameter between 0.1 mm and10 cm. The second positioning element is oval and wherein said oval hasa long axis between 0.1 mm and 10 cm and a short axis between 0.1 mm and5 cm.

In another embodiment, the present specification is directed toward adevice to perform ablation of endometrial tissue, comprising a catheterhaving a hollow shaft through which steam can be delivered, a firstpositioning element attached to said catheter shaft at a first position,wherein said first positioning element is conical and configured tocenter said catheter in a center of a cervix, an optional secondpositioning element attached to said catheter shaft at a secondposition, wherein the second positioning element is disc shaped, aplurality of ports integrally formed in said catheter shaft, whereinsteam can be released out of said ports and directed toward endometrialtissue and wherein said ports are located between said first positionand second position; and at least one temperature sensor.

Optionally, the second positioning element has a dimension, which can beused to determine a uterine cavity size. The second positioning elementhas a dimension, which can be used to calculate an amount of thermalenergy needed to ablate the endometrial tissue. The temperature sensorsare used to control delivery of said ablative agent. The firstpositioning element comprises wire mesh. The second positioning elementhas a disc shape that is oval and wherein said oval has a long axisbetween 0.1 mm and 10 cm and a short axis between 0.1 mm and 5 cm.

The present specification is also directed toward a device to performablation of tissue in a hollow organ, comprising a catheter having ashaft through which an ablative agent can travel; a first positioningelement attached to said catheter shaft at a first position, whereinsaid first positioning element is configured to position said catheterat a predefined distance from the tissue to be ablated; and wherein theshaft comprises one or more port through which said ablative agent canbe released out of said shaft.

Optionally, the device further comprises a second positioning elementattached to said catheter shaft at a position different from said firstpositioning element. The first positioning element is at least one of aconical shape, disc shape, or a free form shape conformed to the shapeof the hollow organ. The second positioning element has predefineddimensions and wherein said predefined dimensions are used to determinethe dimensions of the hollow organ to be ablated. The first positioningelement comprises an insulated membrane. The insulated membrane isconfigured to prevent an escape of thermal energy. The secondpositioning element is at least one of a conical shape, disc shape, or afree form shape conformed to the shape of the hollow organ. The secondpositioning element has predefined dimensions and wherein saidpredefined dimensions are used to determine the dimensions of the holloworgan to be ablated. The second positioning element has a predefineddimension and wherein said predefined dimension is used to calculate anamount of thermal energy needed to ablate the tissue. The device furthercomprises at least one temperature sensor. The temperature sensor isused to control delivery of said ablative agent. The ablative agent issteam. The first positioning element is a covered wire mesh. The firstpositioning element comprises a circular body with a diameter between0.01 mm and 10 cm. The first positioning element is oval and whereinsaid oval has a long axis between 0.01 mm and 10 cm and a short axisbetween 0.01 mm and 9 cm.

In another embodiment, the present specification is directed to a deviceto perform ablation of tissue in a hollow organ, comprising a catheterhaving a hollow shaft through which steam can be delivered; a firstpositioning element attached to said catheter shaft at a first position,wherein said first positioning element is configured to position saidcatheter at a predefined distance from the surface of the hollow organ;a second positioning element attached to said catheter shaft at a secondposition, wherein the second positioning element is shaped to positionsaid catheter at a predefined distance from the surface of the holloworgan; a plurality of ports integrally formed in said catheter shaft,wherein steam can be released out of said ports and directed towardtissue to be ablated and wherein said ports are located between saidfirst position and second position; and at least one temperature sensor.

Optionally, the first positioning element has a predefined dimension andwherein said dimension is used to determine the size of the holloworgan. The second positioning element has a predefined dimension andwherein said dimension is used to calculate an amount of thermal energyneeded to ablate the tissue. The temperature sensor is used to controldelivery of said ablative agent. The first positioning element compriseswire mesh. The second positioning element has a disc shape that is ovaland wherein said oval has a long axis between 0.01 mm and 10 cm and ashort axis between 0.01 mm and 9 cm.

In another embodiment, the present specification is directed to a deviceto perform ablation of the gastrointestinal tissue, comprising acatheter having a shaft through which an ablative agent can travel; afirst positioning element attached to said catheter shaft at a firstposition, wherein said first positioning element is configured toposition the catheter at a fixed distance from the gastrointestinaltissue to be ablated, and wherein said first positioning element isseparated from an ablation region by a distance of between 0 mm and 5cm, and an input port at a second position and in fluid communicationwith said catheter shaft in order to receive said ablative agent whereinthe shaft comprises one or more ports through which said ablative agentcan be released out of said shaft.

Optionally, the first positioning element is at least one of aninflatable balloon, wire mesh disc or cone. By introducing said ablativeagent into said ablation region, the device creates a gastrointestinalpressure equal to or less than 5 atm. The ablative agent has atemperature between −100 degrees Celsius and 200 degrees Celsius. Thecatheter further comprises a temperature sensor. The catheter furthercomprises a pressure sensor. The first positioning element is configuredto abut a gastroesophageal junction when placed in a gastric cardia. Theports are located between said first position and second position. Thediameter of the positioning element is between 0.01 mm and 100 mm. Theablative agent is steam. The first positioning element comprises acircular body with a diameter between 0.01 mm and 10 cm.

In another embodiment, the present specification is directed toward adevice to perform ablation of esophageal tissue, comprising a catheterhaving a hollow shaft through which steam can be transported; a firstpositioning element attached to said catheter shaft at a first position,wherein said first positioning element is configured to abut agastroesophageal junction when placed in a gastric cardia; and an inputport at a second position and in fluid communication with said cathetershaft in order to receive said steam wherein the shaft comprises aplurality of ports through which said steam can be released out of saidshaft and wherein said ports are located between said first position andsecond position. The device further comprises a temperature sensorwherein said temperature sensor is used to control the release of saidsteam. The first positioning element comprises at least one of a wiremesh disc, a wire mesh cone, or an inflatable balloon. The firstpositioning element is separated from an ablation region by a distanceof between 0 mm and 1 cm. The diameter of the first positioning elementis between 1 mm and 100 mm.

In another embodiment, the present specification is directed to a deviceto perform ablation of gastrointestinal tissue, comprising a catheterhaving a hollow shaft through which steam can be transported; a firstpositioning element attached to said catheter shaft at a first position,wherein said first positioning element is configured to abut thegastrointestinal tissue; and an input port at a second position and influid communication with said catheter shaft in order to receive saidsteam wherein the shaft comprises one or more ports through which saidsteam can be released out of said shaft onto the gastrointestinaltissue.

Optionally, the device further comprises a temperature sensor whereinsaid temperature sensor is used to control the release of said steam.The first positioning element comprises at least one of a wire mesh discand a wire mesh cone. The diameter of the first positioning element is0.1 mm to 50 mm. The device is used to perform non-circumferentialablation.

In another embodiment, the present specification is directed to a deviceto perform ablation of endometrial tissue, comprising a catheter havinga shaft through which an ablative agent can travel; a first positioningelement attached to said catheter shaft at a first position, whereinsaid first positioning element is configured to center said catheter ina center of a cervix; and a shaft comprises a plurality of ports throughwhich said ablative agent can be released out of said shaft.

Optionally, the device further comprises a second positioning elementattached to said catheter shaft at a second position. The firstpositioning element is conical. The first positioning element comprisesan insulated membrane. The insulated membrane is configured to preventan escape of thermal energy through the cervix. The second positioningelement is disc shaped. The second positioning element has a predefineddimension and wherein said dimension is used to determine a uterinecavity size. The second positioning element has a predefined dimensionand wherein said dimension is used to calculate an amount of thermalenergy needed to ablate the endometrial tissue. The device furthercomprises at least one temperature sensor wherein said temperaturesensor is used to control delivery of said ablative agent. The ablativeagent is steam. The first positioning element is a covered wire mesh.The first positioning element comprises a circular body with a diameterbetween 0.01 mm and 10 cm. The second positioning element is oval andwherein said oval has a long axis between 0.01 mm and 10 cm and a shortaxis between 0.01 mm and 5 cm. When deployed, the positioning elementsalso serve to open up the uterine cavity.

In another embodiment, the present specification is directed toward adevice to perform ablation of endometrial tissue, comprising a catheterhaving a hollow shaft through which steam can be delivered; a firstpositioning element attached to said catheter shaft at a first position,wherein said first positioning element is conical and configured tocenter said catheter in a center of a cervix; a second positioningelement attached to said catheter shaft at a second position, whereinthe second positioning element is elliptical shaped; a plurality ofports integrally formed in said catheter shaft, wherein steam can bereleased out of said ports and directed toward endometrial tissue andwherein said ports are located between said first position and secondposition; and at least one temperature sensor.

Optionally, the second positioning element has a predefined dimensionand wherein said dimension is used to determine a uterine cavity size.The second positioning element has a diameter and wherein said diameteris used to calculate an amount of thermal energy needed to ablate theendometrial tissue. The temperature sensors are used to control deliveryof said ablative agent. The first positioning element comprises wiremesh. The second positioning element has a disc shape that is oval andwherein said oval has a long axis between 0.01 mm and 10 cm and a shortaxis between 0.01 mm and 5 cm.

Optionally, the second positioning element can use one or more sourcesof infrared, electromagnetic, acoustic or radiofrequency energy tomeasure the dimensions of the hollow cavity. The energy is emitted fromthe sensor and is reflected back to the detector in the sensor. Thereflected data is used to determine the dimension of the hollow cavity.

In one embodiment, the present specification discloses a device to beused in conjunction with a tissue ablation system, comprising: a handlewith a pressure-resistant port on its distal end, a flow channel throughwhich an ablative agent can travel, and one or more connection ports onits proximal end for the inlet of said ablative agent and for an RFfeed; an insulated catheter that attaches to said pressure-resistantport of said snare handle, containing a shaft through which an ablativeagent can travel and one or more ports along its length for the releaseof said ablative agent; and one or more positioning elements attached tosaid catheter shaft at one or more separate positions, wherein saidpositioning element(s) is configured to position said catheter at apredefined distance from the tissue to be ablated.

Optionally, the handle has one pressure-resistant port for theattachment of both an ablative agent inlet and an RF feed. The handlehas one separate pressure-resistant port for the attachment of anablative agent inlet and one separate port for the attachment of an RFfeed or an electrical feed.

In another embodiment, the present specification discloses a device tobe used in conjunction with a tissue ablation system, comprising: ahandle with a pressure-resistant port on its distal end, a flow channelpassing through said handle which is continuous with a pre-attached cordthrough which an ablative agent can travel, and a connection port on itsproximal end for an RF feed or an electrical field; an insulatedcatheter that attaches to said pressure-resistant port of said handle,containing a shaft through which an ablative agent can travel and one ormore ports along its length for the release of said ablative agent; andone or more positioning elements attached to said catheter shaft at oneor more separate positions, wherein said positioning element(s) isconfigured to position said catheter at a predefined distance from thetissue to be ablated. Optionally, the distal end of said catheter isdesigned to puncture the target.

In another embodiment, the present specification discloses a device tobe used in conjunction with a tissue ablation system, comprising: anesophageal probe with a pressure-resistant port on its distal end, aflow channel through which an ablative agent can travel, and one or moreconnection ports on its proximal end for the inlet of said ablativeagent and for an RF feed or an electrical feed; an insulated catheterthat attaches to said pressure-resistant port of said esophageal probe,containing a shaft through which an ablative agent can travel and one ormore ports along its length for the release of said ablative agent; andone or more inflatable positioning balloons at either end of saidcatheter positioned beyond said one or more ports, wherein saidpositioning balloons are configured to position said catheter at apredefined distance from the tissue to be ablated.

Optionally, the catheter is dual lumen, wherein a first lumenfacilitates the transfer of ablative agent and a second lumen containsan electrode for RF ablation. The catheter has differential insulationalong its length.

The present specification is also directed toward a tissue ablationdevice, comprising: a liquid reservoir, wherein said reservoir includesan outlet connector that can resist at least 1 atm of pressure for theattachment of a reusable cord; a heating component comprising: a lengthof coiled tubing contained within a heating element, wherein activationof said heating element causes said coiled tubing to increase from afirst temperature to a second temperature and wherein said increasecauses a conversion of liquid within said coiled tubing to vapor; and aninlet connected to said coiled tubing; an outlet connected to saidcoiled tubing; and at least one pressure-resistant connection attachedto the inlet and/or outlet; a cord connecting the outlet of saidreservoir to the inlet of the heating component; a single use cordconnecting a pressure-resistant inlet port of a vapor based ablationdevice to the outlet of said heating component.

In one embodiment, the liquid reservoir is integrated within anoperating room equipment generator. In one embodiment, the liquid iswater and the vapor is steam.

In one embodiment, the pressure-resistant connections are luer lockconnections. In one embodiment, the coiled tubing is copper.

In one embodiment, the tissue ablation device further comprises a footpedal, wherein only when said foot pedal is pressed, vapor is generatedand passed into said single use cord. In another embodiment, only whenpressure is removed from said foot pedal, vapor is generated and passedinto said single use cord.

In another embodiment, the present specification discloses a vaporablation system used for supplying vapor to an ablation device,comprising; a single use sterile fluid container with attachedcompressible tubing used to connect the fluid source to a heating unitin the handle of a vapor ablation catheter. The tubing passes through apump that delivers the fluid into the heating unit at a predeterminedspeed. There is present a mechanism such as a unidirectional valvebetween the fluid container and the heating unit to prevent the backflowof vapor from the heating unit. The heating unit is connected to theablation catheter to deliver the vapor from the heating unit to theablation site. The flow of vapor is controlled by a microprocessor. Themicroprocessor uses a pre-programmed algorithm in an open-loop system oruses information from one or more sensors incorporated in the ablationsystem in a closed-loop system or both to control delivery of vapor.

In one embodiment, the handle of the ablation device is made of athermally insulating material to prevent thermal injury to the operator.The heating unit is enclosed in the handle. The handle locks into thechannel of an endoscope after the catheter is passed through the channelof the endoscope. The operator can than manipulate the catheter byholding the insulated handle or by manipulating the catheter proximal tothe insulating handle.

The present specification is also directed toward a vapor ablationsystem comprising: a container with a sterile liquid therein; a pump influid communication with said container; a first filter disposed betweenand in fluid communication with said container and said pump; a heatingcomponent in fluid communication with said pump; a valve disposedbetween and in fluid communication with said pump and heating container;a catheter in fluid communication with said heating component, saidcatheter comprising at least one opening at its operational end; and, amicroprocessor in operable communication with said pump and said heatingcomponent, wherein said microprocessor controls the pump to control aflow rate of the liquid from said container, through said first filter,through said pump, and into said heating component, wherein said liquidis converted into vapor via the transfer of heat from said heatingcomponent to said fluid, wherein said conversion of said fluid into saidvapor results is a volume expansion and a rise in pressure where saidrise in pressure forces said vapor into said catheter and out said atleast one opening, and wherein a temperature of said heating componentis controlled by said microprocessor.

In one embodiment, the vapor ablation system further comprises at leastone sensor on said catheter, wherein information obtained by said sensoris transmitted to said microprocessor, and wherein said information isused by said microprocessor to regulate said pump and said heatingcomponent and thereby regulate vapor flow. In one embodiment, the atleast one sensor includes one or more of a temperature sensor, flowsensor, or pressure sensor.

In one embodiment, the vapor ablation system further comprises a screwcap on said liquid container and a puncture needle on said first filter,wherein said screw cap is punctured by said puncture needle to providefluid communication between said container and said first filter.

In one embodiment, the liquid container and catheter are disposable andconfigured for a single use.

In one embodiment, the fluid container, first filter, pump, heatingcomponent, and catheter are connected by sterile tubing and theconnections between said pump and said heating component and saidheating component and said catheter are pressure resistant.

The present specification is also directed toward a tissue ablationsystem comprising: a catheter with a proximal end and a distal end and alumen therebetween, said catheter comprising: a handle proximate theproximal end of said catheter and housing a fluid heating chamber and aheating element enveloping said chamber, a wire extending distally fromsaid heating element and leading to a controller; an insulating sheathextending and covering the length of said catheter and disposed betweensaid handle and said heating element at said distal end of saidcatheter; and, at least one opening proximate the distal end of saidcatheter for the passage of vapor; and, a controller operably connectedto said heating element via said wire, wherein said controller iscapable of modulating energy supplied to said heating element andfurther wherein said controller is capable of adjusting a flow rate ofliquid supplied to said catheter; wherein liquid is supplied to saidheating chamber and then converted to vapor within said heating chamberby a transfer of heat from said heating element to said chamber, whereinsaid conversion of said liquid to vapor results in a volume expansionand a rise in pressure within said catheter, and wherein said rise inpressure pushes said vapor through said catheter and out said at leastone opening.

In one embodiment, the tissue ablation system further comprises apressure resistant fitting attached to the fluid supply and a one-wayvalve in said pressure resistant fitting to prevent a backflow of vaporinto the fluid supply.

In one embodiment, the tissue ablation system further comprises at leastone sensor on said catheter, wherein information obtained by said sensoris transmitted to said microprocessor, and wherein said information isused by said microprocessor to regulate said pump and said heatingcomponent and thereby regulate vapor flow.

In one embodiment, the tissue ablation system further comprises a metalframe within said catheter, wherein said metal frame is in thermalcontact with said heating chamber and conducts heat to said catheterlumen, thereby preventing condensation of said vapor. In variousembodiments, the metal frame comprises a metal skeleton with outwardlyextending fins at regularly spaced intervals, a metal spiral, or a metalmesh and the metal frame comprises at least one of copper, stainlesssteel, or another ferric material.

In one embodiment, the heating element comprises a heating block,wherein said heating block is supplied power by said controller.

In various embodiments, the heating element uses one of magneticinduction, microwave, high intensity focused ultrasound, or infraredenergy to heat said heating chamber and the fluid therein.

The present specification also discloses an ablation catheter for usewith a hollow tissue or organ, comprising: a distal end having at leastone opening for the injection of a conductive medium into said hollowtissue or organ and at least one opening for the delivery of an ablativeagent into said hollow tissue or organ; a proximal end configured toreceive said conductive medium and said ablative agent from a source;and, a shaft, having at least one lumen therewithin, between said distalend and said proximal end.

In one embodiment, the ablation catheter for use with a hollow tissue ororgan further comprises at least one positioning element for positioningsaid catheter proximate target tissue to be ablated. In one embodiment,the ablation catheter further comprises at least one occlusive elementto occlude blood flow to said hollow tissue or organ.

The present specification also discloses a method of treating a disorderof a prostate, the method comprising: introducing an ablation catheterinto the prostate; and, delivering an ablative agent into the prostateand ablating prostate tissue without ablating the prostatic urethra. Inone embodiment, the ablative agent is vapor. In one embodiment, thecatheter is introduced transurethraly. In another embodiment, thecatheter is introduced transrectally.

The present specification also discloses an ablation catheter for use intreating a disorder of the prostate, said catheter comprising: one ormore needles for piercing the prostatic tissue and delivering anablative agent into the prostate; and, one or more positioning elementsto position said needles at a predefined distance in the prostate. Inone embodiment, the ablation catheter further comprises a mechanism tocool a prostatic urethra or a rectal wall.

The present specification also discloses a method for treating benignprostatic hyperplasia of a prostate of a patient comprising the stepsof: inserting a plurality of vapor delivery needles through a urethralwall of the patient in a plurality of locations into a prostate lobe;and, delivering water vapor through the needles into the prostate ateach location to ablate the prostatic tissue.

The present specification also discloses a method of providing ablationto a patient's endometrium comprising the steps of: inserting anablation catheter, said catheter comprising a lumen and vapor deliveryports, through a cervix and a cervical canal into the endometrialcavity; and, delivering an ablative agent through said ablation catheterlumen and said delivery ports and into the endometrial cavity to createendometrial ablation. In one embodiment, the method of providingablation to a patient's endometrium further comprises the step ofmeasuring at least one dimension of the endometrial cavity and usingsaid dimension to determine the delivery of ablative agent. In oneembodiment, the method of providing ablation to a patient's endometriumfurther comprises the step of using a positioning element to positionsaid catheter in the center of the endometrial cavity. In oneembodiment, the positioning element includes an expansion mechanism incontact with endometrial tissue to move said endometrial tissue surfacesaway from the vapor delivery ports of the catheter. In one embodiment,the method of providing ablation to a patient's endometrium furthercomprises the step of using an occlusive element to occlude the cervicalos to prevent leakage of the ablative agent through the os.

The present specification also discloses a method of providing ablativetherapy to a patient's endometrium comprising the steps of: inserting acoaxial vapor ablation catheter, comprising an inner catheter and anouter catheter, through the cervical os and into the cervical canal toocclude the cervical canal; advancing the inner catheter of the coaxialvapor ablation catheter into the endometrial cavity; and, deliveringvapor through vapor delivery ports on the inner catheter into theendometrial cavity to ablate the endometrial tissue. The inner catheteris advanced to the fundus of the uterus, thus measuring the uterinecavity length. The length of inner catheter needed, in-turn determinesthe number of vapor delivery ports that are exposed to deliver theablative agent, thus controlling the amount of ablative agent to bedelivered.

The present specification also discloses a method for hemorrhoidablation comprising the steps of: inserting an ablation device, saiddevice comprising a port for engaging a hemorrhoid, at least one portfor delivery of an ablative agent, and a mechanism to create suction,into a patient's anal canal; engaging the targeted hemorrhoid bysuctioning the hemorrhoid into the ablation device; and, delivering theablative agent to the hemorrhoid to ablate the hemorrhoid.

The present specification also discloses a method of ablating a tissueor organ, comprising the steps of: inserting a catheter into said targettissue or organ; using the catheter to remove contents of said targettissue or organ via suction; using the catheter to replace said removedcontents with a conductive medium; introducing an ablative agent to saidconductive medium, and changing the temperature of said conductivemedium to ablate said tissue or organ.

The present specification also discloses a method of ablating a hollowtissue or organ, comprising the steps of: inserting a catheter into ahollow tissue or organ of a patient, said catheter having a stentcoupled to its distal end; advancing said catheter and stent to targettissue; deploying said stent, wherein said deployment involves releasingsaid stent from said distal end of said catheter, further wherein saiddeployment causes said stent to expand such that it comes into physicalcontact with, and is held in place by, the internal surface of saidhollow tissue or organ; and, delivering ablative agent through saidcatheter and into the lumen of said stent, wherein ablative energy fromsaid ablative agent is transferred from said lumen through said stentand into the surrounding tissue to ablate said tissue.

The present specification also discloses a stent for use with anablation catheter, said stent comprising: a compressible, cylindricalhollow body with a lumen therewithin, said body being comprised of athermally conductive material, wherein said body is transformablebetween a first, compressed configuration for delivery and a second,expanded configuration for deployment; one or more openings for thepassage of thermal energy from said lumen of said stent to the exteriorof said stent; one or more flaps covering said openings to prevent theingrowth of tissue surrounding said stent into the lumen of said stent;and, at least one coupling means to couple said stent to said ablationcatheter for delivery and/or retrieval.

The present specification also discloses an ablation catheter assemblycomprising: a catheter having an elongate body with a lumen within, aproximal end, and a distal end; a first inline chamber having anelongate body with a lumen within, a proximal end, and a distal end,wherein said distal end of said first inline chamber is connected tosaid proximal end of said catheter and said lumen of said first inlinechamber is in fluid communication with said lumen of said catheter,further wherein said first inline chamber is composed of a ferromagneticor thermally conducting material; a second inline chamber having anelongate body with a lumen within, a proximal end, and a distal end,wherein said distal end of said second inline chamber is connected tosaid proximal end of said first inline chamber and said lumen of saidsecond inline chamber is in fluid communication with said lumen of saidfirst inline chamber, further wherein said second inline chamber isconfigured to contain a fluid; an optional one way valve positioned atthe connection between said first inline chamber and said second inlinechamber, said valve allowing flow of fluid from said second inlinechamber into said first inline chamber but not in the reverse direction;and, a piston within and proximate said proximal end of said secondinline chamber; wherein said proximal end of said second inline chamberis connected to an external pump and said pump engages said piston topush a fluid from said second inline chamber into said first inlinechamber where an external heating element heats said first inlinechamber and the transfer of said heat to said fluid causes vaporizationof said fluid, further wherein said vaporized fluid passes through saidelongate body and out said distal end of said catheter.

Optionally, in one embodiment, the ablation catheter assembly furthercomprises a thermally insulated handle on said catheter body. In oneembodiment, the pump is a syringe pump. In one embodiment, the pump iscontrolled by a microprocessor to deliver ablative vapor at apredetermined rate. Optionally, a peristaltic pump or any other pumpknown in the field can be used to push fluid from the second inlinechamber to the first inline chamber at a rate that is controllable by amicroprocessor. In one embodiment, the ablation catheter assemblyfurther comprises at least one sensor on said catheter, whereininformation from said sensor is relayed to said microprocessor and thedelivery rate of ablative vapor is based upon said information.

In one embodiment, the heating element is any one of a resistive heater,an RF heater, a microwave heater and an electromagnetic heater. In oneembodiment, the fluid is water. In one embodiment, the first inlinechamber comprises a plurality of channels within to increase the contactsurface area of said fluid with said first inline chamber. In variousembodiments, the channels comprise any one of metal tubes, metal beads,and metal filings.

In one embodiment, the elongate body of said catheter includes an outersurface and an inner surface and said inner surface includes a groovepattern to decrease the resistance to flow of said fluid within saidcatheter.

Optionally, in one embodiment, the catheter comprises a first inner walland a second outer wall and an insulating layer between said first walland said second wall. In one embodiment, said first inner wall and saidsecond outer wall are connected by a plurality of spokes. In oneembodiment, the insulating layer is filled with air. In anotherembodiment, the insulating layer is filled with a fluid. In anotherembodiment, the insulating layer is made of any thermally insulatingmaterial.

The present specification also discloses a system for heating a fluid,said system comprising: a chamber for containing said fluid, saidchamber defining an enclosed three dimensional space and having aproximal end and a distal end, wherein said proximal end includes aninlet port for delivery of said fluid and said distal end includes anoutlet port, further wherein said chamber is composed of a ferromagneticmaterial; and, an induction heating element positioned around saidchamber, said induction heating element capable of receiving analternating current; wherein, when an alternating current is supplied tosaid induction heating element, a magnetic field is created in the areasurrounding said chamber and said magnetic field induces electriccurrent flow within the ferromagnetic material of said chamber, furtherwherein said electric current flow results in the heating of saidchamber and said heat is transferred to said fluid, converting saidfluid into vapor which exits said chamber through said outlet port.

In various embodiments, the ferromagnetic material comprises any one ofiron, stainless steel, and copper. In various embodiments, theferromagnetic material is a curie material with a curie temperaturebetween 60° C. and 250° C.

In one embodiment, the induction heating element comprises a metal wirecoil looped about said chamber. In one embodiment, the coil is loopedabout a length of said chamber such that said coil is in physicalcontact with said chamber. In other embodiments, the coil is loopedabout a length of said chamber spaced away from said chamber with alayer of air or insulating material between said coil and said chamber.

The present specification also discloses a method for heating a fluid,said method comprising the steps of: providing a chamber for containingsaid fluid, said chamber defining an enclosed three dimensional spaceand having a proximal end and a distal end, wherein said proximal endincludes an inlet port for delivery of said fluid and said distal endincludes an outlet port, further wherein said chamber is composed of aferromagnetic material; surrounding said chamber with an inductionheating element; filling said container with said fluid; providing analternating current to said induction heating element such that amagnetic field is created in the area surrounding said chamber and saidmagnetic field induces electric current flow within the ferromagneticmaterial of said chamber, further wherein said electric current flowresults in the heating of said chamber and said heat is transferred tosaid fluid, converting said fluid into vapor which exits said chamberthrough said outlet port.

The aforementioned and other embodiments of the present invention shallbe described in greater depth in the drawings and detailed descriptionprovided below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will befurther appreciated, as they become better understood by reference tothe detailed description when considered in connection with theaccompanying drawings, wherein:

FIG. 1 illustrates an ablation device, in accordance with an embodimentof the present specification;

FIG. 2A illustrates a longitudinal section of an ablation device withports distributed thereon;

FIG. 2B illustrates a cross section of a port on the ablation device, inaccordance with an embodiment of the present specification;

FIG. 2C illustrates a cross section of a port on the ablation device, inaccordance with another embodiment of the present specification;

FIG. 2D illustrates a catheter of the ablation device, in accordancewith an embodiment of the present specification;

FIG. 2E illustrates a catheter of the ablation device, in accordancewith another embodiment of the present specification;

FIG. 2F illustrates a catheter of the ablation device, in accordancewith yet another embodiment of the present specification;

FIG. 2G is a flow chart listing the steps involved in a hollow tissue ororgan ablation process using an ablation device, in accordance with oneembodiment of the present specification;

FIG. 2H illustrates an ablation device in the form of a catheterextending from a conventional snare handle, in accordance with anembodiment of the present specification;

FIG. 2I illustrates a cross section of an ablation device in the form ofa catheter extending from a conventional snare handle with apre-attached cord, in accordance with another embodiment of the presentspecification;

FIG. 2J illustrates an ablation device in the form of a catheterextending from a conventional esophageal probe, in accordance with anembodiment of the present specification;

FIG. 3A illustrates the ablation device placed in an uppergastrointestinal tract with Barrett's esophagus to selectively ablatethe Barrett's tissue, in accordance with an embodiment of the presentspecification;

FIG. 3B illustrates the ablation device placed in an uppergastrointestinal tract with Barrett's esophagus to selectively ablatethe Barrett's tissue, in accordance with another embodiment of thepresent specification;

FIG. 3C is a flowchart illustrating the basic procedural steps for usingthe ablation device, in accordance with an embodiment of the presentspecification;

FIG. 4A illustrates the ablation device placed in a colon to ablate aflat colon polyp, in accordance with an embodiment of the presentspecification;

FIG. 4B illustrates the ablation device placed in a colon to ablate aflat colon polyp, in accordance with another embodiment of the presentspecification;

FIG. 5A illustrates the ablation device with a coaxial catheter design,in accordance with an embodiment of the present specification;

FIG. 5B illustrates a partially deployed positioning device, inaccordance with an embodiment of the present specification;

FIG. 5C illustrates a completely deployed positioning device, inaccordance with an embodiment of the present specification;

FIG. 5D illustrates the ablation device with a conical positioningelement, in accordance with an embodiment of the present specification;

FIG. 5E illustrates the ablation device with a disc shaped positioningelement, in accordance with an embodiment of the present specification;

FIG. 6 illustrates an upper gastrointestinal tract with a bleedingvascular lesion being treated by the ablation device, in accordance withan embodiment of the present specification;

FIG. 7A illustrates endometrial ablation being performed in a femaleuterus by using the ablation device, in accordance with an embodiment ofthe present specification;

FIG. 7B is an illustration of a coaxial catheter used in endometrialtissue ablation, in accordance with one embodiment of the presentspecification;

FIG. 7C is a flow chart listing the steps involved in an endometrialtissue ablation process using a coaxial ablation catheter, in accordancewith one embodiment of the present specification;

FIG. 8 illustrates sinus ablation being performed in a nasal passage byusing the ablation device, in accordance with an embodiment of thepresent specification;

FIG. 9 illustrates bronchial and bullous ablation being performed in apulmonary system by using the ablation device, in accordance with anembodiment of the present specification;

FIG. 10A illustrates prostate ablation being performed on an enlargedprostrate in a male urinary system by using the device, in accordancewith an embodiment of the present specification;

FIG. 10B is an illustration of transurethral prostate ablation beingperformed on an enlarged prostrate in a male urinary system using anablation device, in accordance with one embodiment of the presentspecification;

FIG. 10C is an illustration of transurethral prostate ablation beingperformed on an enlarged prostrate in a male urinary system using anablation device, in accordance with another embodiment of the presentspecification;

FIG. 10D is a flow chart listing the steps involved in a transurethralenlarged prostate ablation process using an ablation catheter, inaccordance with one embodiment of the present specification;

FIG. 10E is an illustration of transrectal prostate ablation beingperformed on an enlarged prostrate in a male urinary system using anablation device, in accordance with one embodiment of the presentspecification;

FIG. 10F is an illustration of transrectal prostate ablation beingperformed on an enlarged prostrate in a male urinary system using acoaxial ablation device having a positioning element, in accordance withanother embodiment of the present specification;

FIG. 10G is a flow chart listing the steps involved in a transrectalenlarged prostate ablation process using an ablation catheter, inaccordance with one embodiment of the present specification;

FIG. 10H is an illustration of an ablation catheter for permanentimplantation in the body to deliver repeat ablation, in accordance withone embodiment of the present specification;

FIG. 10I is an illustration of a trocar used to place the ablationcatheter of FIG. 10H in the body, in accordance with one embodiment ofthe present specification;

FIG. 10J is an illustration of the catheter of FIG. 10H and the trocarof FIG. 10I assembled for placement of the catheter into tissue targetedfor ablation in the human body, in accordance with one embodiment of thepresent specification;

FIG. 11 illustrates fibroid ablation being performed in a female uterusby using the ablation device, in accordance with an embodiment of thepresent specification;

FIG. 12A illustrates a blood vessel ablation being performed by anablation device, in accordance with one embodiment of the presentspecification;

FIG. 12B illustrates a blood vessel ablation being performed by anablation device, in accordance with another embodiment of the presentspecification;

FIG. 12C is a flow chart listing the steps involved in a blood vesselablation process using an ablation catheter, in accordance with oneembodiment of the present specification;

FIG. 13A illustrates a cyst ablation being performed by an ablationdevice, in accordance with one embodiment of the present specification;

FIG. 13B is a flow chart listing the steps involved in a cyst ablationprocess using an ablation catheter, in accordance with one embodiment ofthe present specification;

FIG. 14 is a flow chart listing the steps involved in a tumor ablationprocess using an ablation catheter, in accordance with one embodiment ofthe present specification;

FIG. 15A illustrates a non-endoscopic device used for internalhemorrhoid ablation, in accordance with one embodiment of the presentspecification;

FIG. 15B is a flow chart listing the steps involved in an internalhemorrhoid ablation process using an ablation device, in accordance withone embodiment of the present specification;

FIG. 16A illustrates an endoscopic device used for internal hemorrhoidablation, in accordance with one embodiment of the presentspecification;

FIG. 16B is a flow chart listing the steps involved in an internalhemorrhoid ablation process using an endoscopic ablation device, inaccordance with one embodiment of the present specification;

FIG. 17A illustrates a stent used to provide localized ablation to atarget tissue, in accordance with one embodiment of the presentspecification;

FIG. 17B illustrates a catheter used to deploy, and provide an ablativeagent to, the stent of FIG. 17A;

FIG. 17C illustrates the stent of FIG. 17A working in conjunction withthe catheter of FIG. 17B;

FIG. 17D illustrates the stent of FIG. 17A and the catheter of FIG. 17Bpositioned in a bile duct obstructed by a pancreatic tumor;

FIG. 17E is a flow chart listing the steps involved in a hollow tissueor organ ablation process using an ablation stent and catheter, inaccordance with one embodiment of the present specification;

FIG. 18 illustrates a vapor delivery system using an RF heater forsupplying vapor to the ablation device, in accordance with an embodimentof the present specification;

FIG. 19 illustrates a vapor delivery system using a resistive heater forsupplying vapor to the ablation device, in accordance with an embodimentof the present specification;

FIG. 20 illustrates a vapor delivery system using a heating coil forsupplying vapor to the ablation device, in accordance with an embodimentof the present specification;

FIG. 21 illustrates the heating component and coiled tubing of theheating coil vapor delivery system of FIG. 20, in accordance with anembodiment of the present specification;

FIG. 22A illustrates the unassembled interface connection between theablation device and the single use cord of the heating coil vapordelivery system of FIG. 20, in accordance with an embodiment of thepresent specification;

FIG. 22B illustrates the assembled interface connection between theablation device and the single use cord of the heating coil vapordelivery system of FIG. 20, in accordance with an embodiment of thepresent specification;

FIG. 23 illustrates a vapor ablation system using a heater or heatexchange unit for supplying vapor to the ablation device, in accordancewith another embodiment of the present specification;

FIG. 24 illustrates the fluid container, filter member, and pump of thevapor ablation system of FIG. 23;

FIG. 25 illustrates a first view of the fluid container, filter member,pump, heater or heat exchange unit, and microcontroller of the vaporablation system of FIG. 23;

FIG. 26 illustrates a second view of the fluid container, filter member,pump, heater or heat exchange unit, and microcontroller of the vaporablation system of FIG. 23;

FIG. 27 illustrates the unassembled filter member of the vapor ablationsystem of FIG. 23, depicting the filter positioned within;

FIG. 28 illustrates one embodiment of the microcontroller of the vaporablation system of FIG. 23;

FIG. 29 illustrates one embodiment of a catheter assembly for use withthe vapor ablation system of FIG. 23;

FIG. 30 illustrates one embodiment of a heat exchange unit for use withthe vapor ablation system of FIG. 23;

FIG. 31A illustrates another embodiment of a heat exchange unit for usewith the vapor ablation system of the present specification;

FIG. 31B illustrates another embodiment of a heat exchange unit for usewith the vapor ablation system of the present specification;

FIG. 32A illustrates the use of induction heating to heat a chamber;

FIG. 32B is a flow chart listing the steps involved in using inductionheating to heat a chamber;

FIG. 33A illustrates one embodiment of a coil used with inductionheating in the vapor ablation system of the present specification;

FIG. 33B illustrates one embodiment of a catheter handle used withinduction heating in the vapor ablation system of the presentspecification;

FIG. 34A is a front view cross sectional diagram illustrating oneembodiment of a catheter used with induction heating in the vaporablation system of the present specification;

FIG. 34B is a longitudinal view cross sectional diagram illustrating oneembodiment of a catheter used with induction heating in the vaporablation system of the present specification;

FIG. 34C is a longitudinal view cross sectional diagram illustratinganother embodiment of a catheter with a metal spiral used with inductionheating in the vapor ablation system of the present specification;

FIG. 34D is a longitudinal view cross sectional diagram illustratinganother embodiment of a catheter with a mesh used with induction heatingin the vapor ablation system of the present specification;

FIG. 35 illustrates one embodiment of a heating unit using microwaves toconvert fluid to vapor in the vapor ablation system of the presentspecification;

FIG. 36A illustrates a catheter assembly having an inline chamber forheat transfer in accordance with one embodiment of the presentspecification;

FIG. 36B illustrates the catheter assembly of FIG. 35A including anoptional handle;

FIG. 36C illustrates the catheter assembly of FIG. 36B connected to agenerator having a heating element and a pump, in accordance with oneembodiment of the present specification;

FIG. 37A illustrates a heating chamber packed with metal tubes inaccordance with one embodiment of the present specification;

FIG. 37B illustrates a heating chamber packed with metal beads inaccordance with one embodiment of the present specification;

FIG. 37C illustrates a heating chamber packed with metal filings inaccordance with one embodiment of the present specification;

FIG. 38A illustrates a cross-sectional view of one embodiment of acatheter having an internal groove to decrease flow resistance;

FIG. 38B illustrates an on-end view of one embodiment of a catheterhaving an internal groove to decrease flow resistance;

FIG. 39A illustrates a cross-sectional view of a double layered catheterin accordance with one embodiment of the present specification; and,

FIG. 39B illustrates a cross-sectional view of a double layered catheterin accordance with another embodiment of the present specification.

DETAILED DESCRIPTION

The present specification is directed toward an ablation devicecomprising a catheter with one or more centering or positioningattachments at one or more ends of the catheter to affix the catheterand its infusion port at a fixed distance from the ablative tissue whichis not affected by the movements of the organ. The arrangement of one ormore spray ports allows for uniform spray of the ablative agentproducing a uniform ablation of a large area, such as encountered inBarrett's esophagus or for endometrial ablation. The flow of ablativeagent is controlled by the microprocessor and depends upon one or moreof the length or area of tissue to be ablated, type and depth of tissueto be ablated, and distance of the infusion port from or in the tissueto be ablated.

The present specification is also directed toward a device to be used inconjunction with a tissue ablation system, comprising: a handle with apressure-resistant port on its distal end, a flow channel through whichan ablative agent can travel, and one or more connection ports on itsproximal end for the inlet of said ablative agent and for an RF feed oran electrical feed; an insulated catheter that attaches to saidpressure-resistant port of said handle, containing a shaft through whichan ablative agent can travel and one or more ports along its length forthe release of said ablative agent; and, one or more positioningelements attached to said catheter shaft at one or more separatepositions, wherein said positioning element(s) is configured to positionsaid catheter at a predefined distance from or in the tissue to beablated.

In one embodiment, the handle has one pressure-resistant port for theattachment of both an ablative agent inlet and an RF feed. In anotherembodiment, the handle has one separate pressure-resistant port for theattachment of an ablative agent inlet and one separate port for theattachment of an RF feed or an electrical feed.

The present specification is also directed toward a device to be used inconjunction with a tissue ablation system, comprising: a handle with apressure-resistant port on its distal end, a flow channel passingthrough said handle which is continuous with a pre-attached cord throughwhich an ablative agent can travel, and a connection port on itsproximal end for an RF feed or an electrical feed; an insulated catheterthat attaches to said pressure-resistant port of said handle, containinga shaft through which an ablative agent can travel and one or more portsalong its length for the release of said ablative agent; and, one ormore positioning elements attached to said catheter shaft at one or moreseparate positions, wherein said positioning element(s) is configured toposition said catheter at a predefined distance from or in the tissue tobe ablated. In one embodiment, the distal end of said catheter isdesigned to puncture the target tissue to deliver ablative agent to thecorrect depth and location.

The present specification is also directed toward a device to be used inconjunction with a tissue ablation system, comprising: an esophagealprobe with a pressure-resistant port on its distal end, a flow channelthrough which an ablative agent can travel, and one or more connectionports on its proximal end for the inlet of said ablative agent and foran RF feed; an insulated catheter that attaches to saidpressure-resistant port of said esophageal probe, containing a shaftthrough which an ablative agent can travel and one or more ports alongits length for the release of said ablative agent; and, one or moreinflatable positioning balloons at either end of said catheterpositioned beyond said one or more ports, wherein said positioningballoons are configured to position said catheter at a predefineddistance from the tissue to be ablated.

In one embodiment, the catheter is dual lumen, wherein a first lumenfacilitates the transfer of ablative agent and a second lumen containsan electrode for RF ablation.

In one embodiment, the catheter has differential insulation along itslength.

The present specification is also directed toward a vapor deliverysystem used for supplying vapor to an ablation device, comprising: aliquid reservoir, wherein said reservoir includes a pressure-resistantoutlet connector for the attachment of a reusable cord; a reusable cordconnecting the outlet of said reservoir to the inlet of a heatingcomponent; a powered heating component containing a length of coiledtubing within for the conversion of liquid to vapor andpressure-resistant connections on both the inlet and outlet ends of saidheating component; and, a single use cord connecting apressure-resistant inlet port of a vapor based ablation device to theoutlet of said heating component.

In one embodiment, the liquid reservoir is integrated within anoperating room equipment generator.

In one embodiment, the liquid is water and resultant said vapor issteam.

In one embodiment, the pressure-resistant connections are of a luer locktype.

In one embodiment, the coiled tubing is copper.

In one embodiment, the vapor delivery system used for supplying vapor toan ablation device further comprises a foot pedal used by the operatorto deliver more vapor to the ablation device.

The present specification is also directed toward a device and a methodfor ablating a hollow tissue or organ by replacing the natural contentsof the tissue or organ with a conductive medium and then delivering anablative agent to the conductive medium to ablate the tissue or organ.

The present specification is also directed toward a device and methodfor ablating a blood vessel consisting of replacing the blood in thetargeted vessel with a conductive medium and then delivering an ablativeagent to the conductive medium to ablate the vessel. In one embodiment,the device and method further comprise a means or step for stopping theflood of blood into the target vessel. In one embodiment, blood flow isoccluded by the application of a tourniquet proximal to the targetvessel. In another embodiment, blood flow is occluded by the applicationof at least one intraluminal occlusive element. In one embodiment, theat least one intraluminal occlusive element includes at least oneunidirectional valve. In one embodiment, the intraluminal occlusiveelement is used to position the source or port delivering the ablativeagent in the vessel.

The present specification is also directed toward a device and a methodfor ablating a cyst by inserting a catheter into the cyst, replacing aportion of the contents of the cyst with a conductive medium, adding anablative agent to the conductive medium, and conducting ablative energyto the cyst wall through the medium to ablate the cyst.

The present specification is also directed toward a device and a methodfor ablating a tumor by inserting a catheter into the tumor, replacing aportion of the contents of the tumor with a conductive medium, adding anablative agent to the conductive medium, and conducting ablative energyto the tumor wall through the medium to ablate the tumor.

In various embodiments, any one of the devices described above comprisesa catheter and includes at least one port for delivering the conductivemedium and at least one separate port for delivering the ablative agent.In another embodiment, the device comprises a catheter and includes atleast one port for delivering both the conductive medium and theablative agent. Optionally, in one embodiment, the device furtherincludes at least one port for removing the contents of the hollow organor tissue or for removing the conductive medium. In various embodiments,the at least one port for removing contents or conductive medium is thesame port for delivering the conductive medium and/or ablative agent oris a separate port. In one embodiment, the ablative agent is a thermalagent, such as steam. In another embodiment, the ablative agent is acryogen, such as liquid nitrogen.

Optionally, in one embodiment, sensors are included in the device tomeasure and control the flow of the ablative agent. In one embodiment,conductive medium is water. In another embodiment, the conductive mediumis saline.

In various embodiments, any one of the devices described above comprisesa coaxial catheter having an outer, insulating sheath and an innertubular member for delivery of the conductive medium and the ablativeagent.

Optionally, in various embodiments, any one of the devices describedabove includes echogenic elements to assist with the placement of thedevice into the target tissue under ultrasonic guidance. Optionally, invarious embodiments, any one of the devices described above includesradio-opaque elements to assist with the placement of the device intothe target tissue under radiologic guidance.

The present specification is also directed toward a system and method ofinternal hemorrhoid ablation by inserting a hollow, tubular device intoa patient's rectum, applying suction to the device to draw the targethemorrhoid tissue into a slot in the device, and delivering an ablativeagent, such as steam, through a port in the device to ablate thehemorrhoid. In one embodiment, the system includes a device composed ofa thermally insulated material to avoid transfer of vapor heat tosurrounding rectal mucosa. In another embodiment, the system has amechanism for puncturing the mucosa to deliver the ablative agentdirectly into the submucosa closer to the hemorrhoid. In anotherembodiment, the system has a mechanism for cooling the mucosa so as toreduce the ablative damage to the mucosa.

The present specification is also directed toward a system and method ofinternal hemorrhoid ablation by inserting a hollow, tubular device intoa patient's rectum, applying suction to the device to draw the targethemorrhoid tissue into a slot in the device, inserting a needle throughthe slot and into the rectal submucosa or the wall of the hemorrhoidvessel, and delivering an ablative agent through the needle to ablatethe hemorrhoid.

The present specification is also directed toward a device and methodfor endometrial treatment by inserting a coaxial catheter comprising aninternal catheter and an external catheter into the cervix, wherein theexternal catheter engages the cervix and the internal catheter extendsinto the uterus. The internal catheter continues until it reaches thefundus of the uterus, at which point the depth of insertion of theinternal catheter is used to measure the depth of the uterine cavity. Anablative agent, such as steam, is then delivered via the at least oneport on the internal catheter to provide treatment to the endometrium.Optionally, in various embodiments, the catheter includes pressuresensors and/or temperature sensors to measure the intrauterine pressureor temperature. Optionally, in one embodiment, the external catheterfurther comprises a plurality of fins which engage the cervix andprevent the escape of ablative agent. In one embodiment, the fins arecomposed of silicon. Optionally in one embodiment, the coaxial catheterfurther includes a locking mechanism between the external catheter andinternal catheter that, when engaged, prevents the escape of ablativeagent. In one embodiment, the locking mechanism is of a luer lock type.Optionally, the flow of ablative agent is controlled by the number ofopen ports which in turn is controlled by the length of the exposedinternal catheter.

The present specification is also directed toward device and method fortissue ablation comprising a stent covered by a membrane that conductsan ablative agent, such as steam, or ablative energy from inside thestent lumen to the external surface of the stent for ablation ofsurrounding tissue. In one embodiment, the stent has a pre-deploymentshape and a post-deployment shape. The pre-deployment shape isconfigured to assist with placement of the stent. In one embodiment, themembrane is composed of a thermally conductive material. In oneembodiment, the membrane includes a plurality of openings that allow forthe passage of ablative agent or energy from the stent lumen to thetissue surrounding the stent. In one embodiment, the stent is used totreat obstruction in a hollow organ. In one embodiment, the membrane ismade of a thermally conductive material that allows for transfer ofenergy from the inside of the stent to the outside of the stent into thesurrounding tissue.

In one embodiment, a catheter is used to deliver the ablative agent tothe stent. The catheter includes at least one port at its distal end forthe delivery of ablative agent into the lumen of the stent. In oneembodiment, the catheter includes one or more positioning elementsconfigured to fix the catheter at a predefined distance from the stent.The positioning element(s) also acts as an occlusive member to preventthe flow of ablative agent out of the ends of the stent. In oneembodiment, the catheter is composed of a thermally insulating material.Optionally, in various embodiments, the catheter includes additionallumens for the passage of a guidewire or radiologic contrast material.

The present specification is also directed toward a device and methodfor transrectal prostate ablation. An endoscope is inserted into therectum for visualization of the prostate. In one embodiment, theendoscope is an echoendoscope. In another embodiment, the visualizationis achieved via transrectal ultrasound. A catheter with a needle tip ispassed transrectally into the prostate and an ablative agent, such asvapor, is delivered through the needle tip and into the prostatictissue. In one embodiment, the needle tip is an echotip or sonolucenttip that can be detected by the echoendoscope to aid in placement withinthe prostatic tissue. In one embodiment, the catheter and needle tip arecomposed of a thermally insulating material. Optionally, in oneembodiment, an additional catheter is placed in the patient's urethra toinsert fluid to cool the prostatic urethra. In one embodiment, thecooling fluid has a temperature of less than 37° C. Optionally, in oneembodiment, the catheter further comprises a positioning element whichpositions the needle tip at a predetermined depth in the prostatictissue. In one embodiment, the positioning element is a compressibledisc.

The present specification is also directed toward an ablation catheterassembly comprising a catheter body, a first inline chamber for heatingan ablative agent, and a second inline chamber for storing said ablativeagent. A pump drives a piston located within the second inline chamberto push a fluid through a one-way valve and into the first inlinechamber. A heating element heats the first inline chamber, convertingthe fluid from a liquid into a vapor. The vapor then travels through thecatheter and is delivered to the target tissue site for ablation. Invarious embodiments, the first chamber is composed of a ferromagnetic orthermally conducting material. In one embodiment, the pump is controlledby a microprocessor to deliver ablative agent at a predetermined rate.In one embodiment, sensors in the catheter provide informationmicroprocessor to control the delivery rate. In one embodiment, thecatheter includes an insulated handle to allow for safe manipulation ofthe catheter assembly by an operator. In various embodiments, theheating element is a resistive heater, RF heater, microwave heater, orelectromagnetic heater.

In various embodiments, the first inline chamber comprises a pluralityof channels within to increase the contact surface area of the ablativeagent with the walls of the chamber to provide for more efficientheating of said agent. In various embodiments, the channels comprisemetal tubes, metal beads, or metal filings. In one embodiment, the innersurface of the catheter includes a groove pattern to reduce theresistance to flow of the ablative agent within the catheter. In oneembodiment, the catheter comprises two walls, an inner wall and an outerwall, with a thin insulating layer in between, to insulate the catheterand prevent thermal trauma to an operator from the heated ablative agentwithin said catheter.

In various embodiments, the ablation devices and catheters described inthe present specification are used in conjunction with any one or moreof the heating systems described in U.S. patent application Ser. No.13/486,980, entitled “Method and Apparatus for Tissue Ablation”, filedon Jun. 1, 2012 and assigned to the applicant of the present invention,which is herein incorporated by reference in its entirety.

“Treat,” “treatment,” and variations thereof refer to any reduction inthe extent, frequency, or severity of one or more symptoms or signsassociated with a condition.

“Duration” and variations thereof refer to the time course of aprescribed treatment, from initiation to conclusion, whether thetreatment is concluded because the condition is resolved or thetreatment is suspended for any reason. Over the duration of treatment, aplurality of treatment periods may be prescribed during which one ormore prescribed stimuli are administered to the subject.

“Period” refers to the time over which a “dose” of stimulation isadministered to a subject as part of the prescribed treatment plan.

The term “and/or” means one or all of the listed elements or acombination of any two or more of the listed elements.

The terms “comprises” and variations thereof do not have a limitingmeaning where these terms appear in the description and claims.

Unless otherwise specified, “a,” “an,” “the,” “one or more,” and “atleast one” are used interchangeably and mean one or more than one.

For any method disclosed herein that includes discrete steps, the stepsmay be conducted in any feasible order. And, as appropriate, anycombination of two or more steps may be conducted simultaneously.

Also herein, the recitations of numerical ranges by endpoints includeall numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, 5, etc.). Unless otherwise indicated, all numbersexpressing quantities of components, molecular weights, and so forthused in the specification and claims are to be understood as beingmodified in all instances by the term “about.” Accordingly, unlessotherwise indicated to the contrary, the numerical parameters set forthin the specification and claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent specification. At the very least, and not as an attempt to limitthe doctrine of equivalents to the scope of the claims, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the specification are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. All numerical values, however, inherently contain a rangenecessarily resulting from the standard deviation found in theirrespective testing measurements.

Ablative agents such as steam, heated gas or cryogens, such as, but notlimited to, liquid nitrogen are inexpensive and readily available andare directed via the infusion port onto the tissue, held at a fixed andconsistent distance, targeted for ablation. This allows for uniformdistribution of the ablative agent on the targeted tissue. The flow ofthe ablative agent is controlled by a microprocessor according to apredetermined method based on the characteristic of the tissue to beablated, required depth of ablation, and distance of the port from thetissue. The microprocessor may use temperature, pressure or othersensing data to control the flow of the ablative agent. In addition, oneor more suction ports are provided to suction the ablation agent fromthe vicinity of the targeted tissue. The targeted segment can be treatedby a continuous infusion of the ablative agent or via cycles of infusionand removal of the ablative agent as determined and controlled by themicroprocessor.

It should be appreciated that the devices and embodiments describedherein are implemented in concert with a controller that comprises amicroprocessor executing control instructions. The controller can be inthe form of any computing device, including desktop, laptop, and mobiledevice, and can communicate control signals to the ablation devices inwired or wireless form.

The present invention is directed towards multiple embodiments. Thefollowing disclosure is provided in order to enable a person havingordinary skill in the art to practice the invention. Language used inthis specification should not be interpreted as a general disavowal ofany one specific embodiment or used to limit the claims beyond themeaning of the terms used therein. The general principles defined hereinmay be applied to other embodiments and applications without departingfrom the spirit and scope of the invention. Also, the terminology andphraseology used is for the purpose of describing exemplary embodimentsand should not be considered limiting. Thus, the present invention is tobe accorded the widest scope encompassing numerous alternatives,modifications and equivalents consistent with the principles andfeatures disclosed. For purpose of clarity, details relating totechnical material that is known in the technical fields related to theinvention have not been described in detail so as not to unnecessarilyobscure the present invention.

FIG. 1 illustrates an ablation device, in accordance with an embodimentof the present specification. The ablation device comprises a catheter10 having a distal centering or positioning attachment which is aninflatable balloon 11. The catheter 10 is made of or covered with aninsulated material to prevent the escape of ablative energy from thecatheter body. The ablation device comprises one or more infusion ports12 for the infusion of ablative agent and one or more suction ports 13for the removal of ablative agent. In one embodiment, the infusion port12 and suction port 13 are the same. In one embodiment, the infusionports 12 can direct the ablative agent at different angles. Ablativeagent is stored in a reservoir 14 connected to the catheter 10. Deliveryof the ablative agent is controlled by a microprocessor 15 andinitiation of the treatment is controlled by a treating physician usingan input device, such as a foot-paddle 16. In other embodiments, theinput device could be a voice recognition system (that is responsive tocommands such as “start”, “more”, “less”, etc.), a mouse, a switch,footpad, or any other input device known to persons of ordinary skill inthe art. In one embodiment, microprocessor 15 translates signals fromthe input device, such as pressure being placed on the foot-paddle orvocal commands to provide “more” or “less” ablative agent, into controlsignals that determine whether more or less ablative agent is dispensed.Optional sensor 17 monitors changes in an ablative tissue or itsvicinity to guide flow of ablative agent. In one embodiment, optionalsensor 17 also includes a temperature sensor. Optional infrared,electromagnetic, acoustic or radiofrequency energy emitters and sensors18 measure the dimensions of the hollow organ.

In one embodiment, a user interface included with the microprocessor 15allows a physician to define device, organ, and condition which in turncreates default settings for temperature, cycling, volume (sounds), andstandard RF settings. In one embodiment, these defaults can be furthermodified by the physician. The user interface also includes standarddisplays of all key variables, along with warnings if values exceed orgo below certain levels.

The ablation device also includes safety mechanisms to prevent usersfrom being burned while manipulating the catheter, including insulation,and optionally, cool air flush, cool water flush, and alarms/tones toindicate start and stop of treatment.

In one embodiment, the inflatable balloon has a diameter of between 1 mmand 10 cm. In one embodiment, the inflatable balloon is separated fromthe ports by a distance of 1 mm to 10 cm. In one embodiment, the size ofthe port openings is between 1 μm and 1 cm. It should be appreciatedthat the inflatable balloon is used to fix the device and therefore isconfigured to not contact the ablated area. The inflatable balloon canbe any shape that contacts the hollow organ at 3 or more points. One ofordinary skill in the art will recognize that, using triangulation, onecan calculate the distance of the catheter from the lesion.Alternatively, the infrared, electromagnetic, acoustic or radiofrequencyenergy emitters and sensors 18 can measure the dimensions of the holloworgan. The infrared, electromagnetic, acoustic or radiofrequency energyis emitted from the emitter 18 and is reflected back from the tissue tothe detector in the emitter 18. The reflected data can be used todetermine the dimension of the hollow cavity. It should be appreciatedthat the emitter and sensor 18 can be incorporated into a singletransceiver that is capable of both emitting energy and detecting thereflected energy.

FIG. 2A illustrates a longitudinal section of the ablation device,depicting a distribution of infusion ports. FIG. 2B illustrates a crosssection of a distribution of infusion ports on the ablation device, inaccordance with an embodiment of the present specification. Thelongitudinal and cross sectional view of the catheter 10 as illustratedin FIGS. 2A and 2B respectively, show one arrangement of the infusionports 12 to produce a uniform distribution of ablative agent 21 in orderto provide a circumferential area of ablation in a hollow organ 20. FIG.2C illustrates a cross section of a distribution of infusion ports onthe ablation device, in accordance with another embodiment of thepresent specification. The arrangement of the infusion ports 12 asillustrated in FIG. 2C produce a focal distribution of ablative agent 21and a focal area of ablation in a hollow organ 20.

For all embodiments described herein, it should be appreciated that thesize of the port, number of ports, and distance between the ports willbe determined by the volume of ablative agent needed, pressure that thehollow organ can withstand, size of the hollow organ as measured by thedistance of the surface from the port, length of the tissue to beablated (which is roughly the surface area to be ablated),characteristics of the tissue to be ablated and depth of ablationneeded. In one embodiment, there is at least one port opening that has adiameter between 1 μm and 1 cm. In another embodiment, there are two ormore port openings that have a diameter between 1 μm and 1 cm and thatare equally spaced around the perimeter of the device.

FIG. 2D illustrates another embodiment of the ablation device. The vaporablation catheter comprises an insulated catheter 21 with one or morepositioning attachments 22 of known length 23. The vapor ablationcatheter has one or more vapor infusion ports 25. The length 24 of thevapor ablation catheter 21 with infusion ports 25 is determined by thelength or area of the tissue to be ablated. Vapor 29 is deliveredthrough the vapor infusion ports 25. The catheter 21 is preferablypositioned in the center of the positioning attachment 22, and theinfusion ports 25 are arranged circumferentially for circumferentialablation and delivery of vapor. In another embodiment, the catheter 21can be positioned toward the periphery of the positioning attachment 22and the infusion ports 25 can be arranged non-circumferentially,preferably linearly on one side for focal ablation and delivery ofvapor. The positioning attachment 22 is one of an inflatable balloon, awire mesh disc with or without an insulated membrane covering the disc,a cone shaped attachment, a ring shaped attachment or a freeformattachment designed to fit the desired hollow body organ or hollow bodypassage, as further described below. Optional infrared, electromagnetic,acoustic or radiofrequency energy emitters and sensors 28 areincorporated to measure the dimensions of the hollow organ.

The vapor ablation catheter may also comprise an optional coaxial sheet27 to restrain the positioning attachment 22 in a manner comparable to acoronary metal stent. In one embodiment, the sheet is made of memorymetal or memory material with a compressed linear form and anon-compressed form in the shape of the positioning attachment.Alternatively, the channel of an endoscope may perform the function ofrestraining the positioning attachment 22 by, for example, acting as aconstraining sheath. Optional sensor 26 is deployed on the catheter tomeasure changes associated with vapor delivery or ablation. The sensoris one of temperature, pressure, photo or chemical sensor.

Optionally, one or more, infrared, electromagnetic, acoustic orradiofrequency energy emitters and sensors 28 can measure the dimensionsof the hollow organ. The infrared, electromagnetic, acoustic orradiofrequency energy is emitted from the emitter 28 and is reflectedback from the tissue to the detector in the emitter 28. The reflecteddata can be used to determine the dimension of the hollow cavity. Themeasurement is performed at one or multiple points to get an accurateestimate of the dimension of the hollow organ. The data can also be usedto create a topographic representation of the hollow organ. Additionaldata from diagnostic tests can be used to validate or add to the datafrom the above measurements.

FIG. 2E illustrates a catheter 21 of the ablation device, in accordancewith another embodiment of the present specification. The catheter 21 issimilar to that described with reference to FIG. 2D, however, thecatheter 21 of FIG. 2E additionally includes at least one port 19 forthe delivery of a conductive medium 31. In one embodiment, theconductive medium 31 is injected into the hollow tissue or organ priorto the introduction of the ablative agent 29. Once the tissue has beenfilled to an appropriate level with the conductive medium 31, ablativeagent 29 is then delivered into the conductive medium 31 filled tissue.The conductive medium 31 acts to evenly distribute the ablative agent29, resulting in more consistent and effective ablation of the targettissue.

FIG. 2F illustrates a catheter 21 of the ablation device, in accordancewith yet another embodiment of the present specification. The catheter21 is similar to that described with reference to FIG. 2E, however, thecatheter 21 of FIG. 2F additionally includes at least one port 30 forthe removal via suction of the natural contents of the hollow tissue ororgan. In one embodiment, the natural contents of the hollow tissue ororgan are removed prior to the introduction of the conductive medium 31or the ablative agent 29.

In another embodiment, as depicted in FIG. 2E, wherein the catheterincludes at least one port 25 for the delivery of ablative agent and atleast one other port 19 for the delivery of a conductive medium, thenatural contents of the hollow tissue or organ can be removed viasuction using the ablative agent delivery port 25. In anotherembodiment, as depicted in FIG. 2E, wherein the catheter includes atleast one port 25 for the delivery of ablative agent and at least oneother port 19 for the delivery of a conductive medium, the naturalcontents of the hollow tissue or organ can be removed via suction usingthe conductive medium delivery port 19. In yet another embodiment, asdepicted in FIG. 2D, the conductive medium can be delivered, and, thenatural contents of the hollow tissue or organ can be removed viasuction, using the ablative agent delivery port 25. In variousembodiments, after ablation of the target tissue(s), the remainingcontents of the hollow tissue or organ are removed via suction using oneor more of the ports described above.

In various embodiments, with respect to the catheters depicted in FIGS.2A-2F, the ablative agent can be any one of steam, liquid nitrogen, orany other suitable ablative agent.

FIG. 2G is a flow chart listing the steps involved in a hollow tissue ororgan ablation process using the ablation device, in accordance with oneembodiment of the present specification. At step 202, an endoscope isinserted into a patient. An ablation device comprising a catheter inaccordance with one embodiment of the present specification, is advancedthrough a working channel of the endoscope and to a target tissue atstep 204. At step 206, the distal end or tip of the catheter is insertedinto the target hollow tissue or organ. Then, at step 208, suction isapplied at the proximal end of the catheter to remove the naturalcontents of the hollow tissue or organ. A conductive medium is theninjected, at step 210, into the hollow tissue or organ via at least oneport on the distal end of the catheter. At step 212, an ablative agentis delivered into the conductive medium for ablation of the targettissue. At step 214, the remaining contents of the tissue, includingconductive medium and ablative agent, are removed via suction using thecatheter. In another embodiment, step 214 is optional, and the remainingcontents of the hollow tissue or organ are reabsorbed by the body. Inanother embodiment, the removal of the natural contents of the hollowtissue or organ at step 208 is optional, and the procedure movesdirectly to the injection of conductive medium at step 210 from enteringthe target tissue with the catheter at step 206.

FIG. 2H illustrates an ablation device 20 in the form of a catheter 21extending from a conventional handle 22, in accordance with anembodiment of the present specification. The catheter 21 is of a type asdescribed above and extends from and attaches to the handle 22. In oneembodiment, the catheter 21 is insulated to protect the user from burnsthat could result from hot vapor heating the catheter. In oneembodiment, the catheter is composed of a material that will ensure thatthe outer temperature of the catheter will remain below 60° C. duringuse. The handle 22 includes a pressure resistant port at the point ofattachment with the catheter 21. The handle 22 also includes a flowchannel within that directs vapor through to the catheter 21.

In one embodiment, the snare handle 22 includes a single attachment port23 for the connection of a vapor stream and an RF feed. In anotherembodiment (not shown), the snare handle includes two separateattachment ports for the connection of a vapor stream and an RF feed.The attachment port 23 interfaces with the vapor supply cord viapressure-resistant connectors. In one embodiment, the connectors are ofa luer lock type. In one embodiment, the catheter 21 is a dual lumencatheter. The first lumen serves to deliver vapor to the site ofablation. In one embodiment, the vapor is released through small ports24 positioned proximate the distal end of the catheter 21. The distalend of the catheter 21 is designed so that it can puncture the tissue todeliver vapor to the desired depth and location within the targettissue. In one embodiment, the distal end of the catheter 21 tapers to apoint. The second lumen houses the electrode used for RF ablation. Inone embodiment, the delivery of vapor or RF waves is achieved throughthe use of a microprocessor. In another embodiment, the user can releasevapor or subject the target tissue to RF waves by the use of actuators(not shown) on the handle 22. In one embodiment, the catheter hasvarying or differential insulation along its length. In one embodiment,the ablation device 20 includes a mechanism in which a snare to graspthe tissue to be ablated and sizing the tissue in the snare is used todetermine the amount of vapor to be delivered.

FIG. 2I illustrates a cross section of an ablation device 27 in the formof a catheter 21 extending from a conventional handle 22 with apre-attached cord 25, in accordance with another embodiment of thepresent specification. The cord 25 attaches directly to the vapordelivery system, eliminating one interface between the system and theablation device and thereby decreasing the chance of system failure as aresult of disconnection. In this embodiment, the handle 22 includes aseparate attachment port (not shown) for the RF or an electric feed.

FIG. 2J illustrates an ablation device 29 in the form of a catheter 21extending from a conventional esophageal probe 26, in accordance with anembodiment of the present specification. In one embodiment, the catheter21 is insulated and receives vapor from a flow channel contained withinthe probe 26. The catheter 21 includes a multitude of small ports 24 forthe delivery of vapor to the target tissue. The delivery of vapor iscontrolled by a microprocessor. In one embodiment, the catheter 21 alsoincludes two inflatable balloons 28, one at its distal end beyond thelast vapor port 24, and one at its proximal end, proximate thecatheter's 21 attachment to the probe 26. All vapor ports are positionedbetween these two balloons. Once the device 29 is inserted within theesophagus, the balloons 28 are inflated to keep the catheter 21positioned and to contain the vapor within the desired treatment area.In one embodiment, the balloons must be separated from the ablationregion by a distance of greater than 0 mm, preferably 1 mm and ideally 1cm. In one embodiment, the diameter of each balloon when inflated is inthe range of 10 to 100 mm, preferably 15-40 mm, although one of ordinaryskill in the art would appreciate that the precise dimensions aredependent on the size of the patient's esophagus.

In one embodiment, the catheter 21 attached to the esophageal probe 26is a dual lumen catheter. The first lumen serves to deliver vapor to thesite of ablation as described above. The second lumen houses theelectrode used for RF ablation.

FIG. 3A illustrates the ablation device placed in an uppergastrointestinal tract with Barrett's esophagus to selectively ablatethe Barrett's tissue, in accordance with an embodiment of the presentspecification. The upper gastrointestinal tract comprises Barrett'sesophagus 31, gastric cardia 32, gastroesophageal junction 33 anddisplaced squamo-columnar junction 34. The area between thegastroesophageal junction 33 and the displaced squamo-columnar junction34 is Barrett's esophagus 31, which is targeted for ablation. Distal tothe cardia 32 is the stomach 35 and proximal to the cardia 32 is theesophagus 36. The ablation device is passed into the esophagus 36 andthe positioning device 11 is placed in the gastric cardia 32 abuttingthe gastroesophageal junction 33. This affixes the ablation catheter 10and its ports 12 in the center of the esophagus 36 and allows foruniform delivery of the ablative agent 21 to the Barrett's esophagus 31.

In one embodiment, the positioning device is first affixed to ananatomical structure, not being subjected to ablation, before ablationoccurs. Where the patient is undergoing circumferential ablation orfirst time ablation, the positioning attachment is preferably placed inthe gastric cardia, abutting the gastroesophageal junction. Where thepatient is undergoing a focal ablation of any residual disease, it ispreferable to use the catheter system shown in FIG. 4B, as discussedbelow. In one embodiment, the positioning attachment must be separatedfrom the ablation region by a distance of greater than 0 mm, preferably1 mm and ideally 1 cm. In one embodiment, the size of the positioningdevice is in the range of 10 to 100 mm, preferably 20-40 mm, althoughone of ordinary skill in the art would appreciate that the precisedimensions are dependent on the size of the patient's esophagus.

The delivery of ablative agent 21 through the infusion port 12 iscontrolled by the microprocessor 15 coupled with the ablation device.The delivery of ablative agent is guided by predetermined programmaticinstructions, depending on the tissue to be ablated and the depth ofablation required. In one embodiment, the target procedural temperaturewill need to be between −100 degrees Celsius and 200 degrees Celsius,preferably between 50 degrees Celsius and 75 degrees Celsius, as furthershown in the dosimetery table below. In one embodiment, esophagealpressure should not exceed 5 atm, and is preferably below 0.5 atm. Inone embodiment, the target procedural temperature is achieved in lessthan 1 minute, preferably in less than 5 seconds, and is capable ofbeing maintained for up to 10 minutes, preferably 1 to 10 seconds, andthen cooled to body temperature. One of ordinary skill in the art wouldappreciate that the treatment can be repeated until the desired ablationeffect is achieved.

Optional sensor 17 monitors intraluminal parameters such as temperatureand pressure and can increase or decrease the flow of ablative agent 21through the infusion port 12 to obtain adequate heating or cooling,resulting in adequate ablation. The sensor 17 monitors intraluminalparameters such as temperature and pressure and can increase or decreasethe removal of ablative agent 21 through the optional suction port 13 toobtain adequate heating or cooling resulting in adequate ablation ofBarrett's esophagus 31. FIG. 3B illustrates the ablation device placedin an upper gastrointestinal tract with Barrett's esophagus toselectively ablate the Barrett's tissue, in accordance with anotherembodiment of the present specification. As illustrated in FIG. 3B, thepositioning device 11 is a wire mesh disc. In one embodiment, thepositioning attachment must be separated from the ablation region by adistance of greater than 0 mm, preferably 1 mm and ideally 1 cm. In oneembodiment, the positioning attachment is removably affixed to thecardia or gastroesophageal (EG) junction (for the distal attachment) orin the esophagus by a distance of greater than 0.1 mm, preferably around1 cm, above the proximal most extent of the Barrett's tissue (for theproximal attachment).

FIG. 3B is another embodiment of the Barrett's ablation device where thepositioning element 11 is a wire mesh disc. The wire mesh may have anoptional insulated membrane to prevent the escape of the ablative agent.In the current embodiment, two wire mesh discs are used to center theablation catheter in the esophagus. The distance between the two discsis determined by the length of the tissue to be ablated which, in thiscase, would be the length of the Barrett's esophagus. Optional infrared,electromagnetic, acoustic or radiofrequency energy emitters and sensors18 are incorporated to measure the diameter of the esophagus.

FIG. 3C is a flowchart illustrating the basic procedural steps for usingthe ablation device, in accordance with an embodiment of the presentspecification. At step 302, a catheter of the ablation device isinserted into an organ which is to be ablated. For example, in order toperform ablation in a Barrett's esophagus of a patient, the catheter isinserted into the Barrett's esophagus via the esophagus of the patient.

At step 304, a positioning element of the ablation device is deployedand organ dimensions are measured. In an embodiment, where thepositioning element is a balloon, the balloon is inflated in order toposition the ablation device at a known fixed distance from the tissueto be ablated. In various embodiments, the diameter of the hollow organmay be predetermined by using radiological tests such as barium X-raysor computer tomography (CT) scan, or by using pressure volume cycle,i.e. by determining volume needed to raise pressure to a fixed level(for example, 1 atm) in a fixed volume balloon. In another embodiment,where the positioning device is disc shaped, circumferential rings areprovided in order to visually communicate to an operating physician thediameter of the hollow organ. In various embodiments of the presentspecification, the positioning device enables centering of the catheterof the ablation device in a non-cylindrical body cavity, and the volumeof the cavity is measured by the length of catheter or a uterine sound.

Optionally, one or more infrared, electromagnetic, acoustic orradiofrequency energy emitters and sensors can be used to measure thedimensions of the hollow organ. The infrared, electromagnetic, acousticor radiofrequency energy is emitted from the emitter and is reflectedback from the tissue to a detector in the emitter. The reflected datacan be used to determine the dimensions of the hollow cavity. Themeasurement can be performed at one or multiple points to get anaccurate estimate of the dimensions of the hollow organ. The data frommultiple points can also be used to create a topographic representationof the hollow organ or to calculate the volume of the hollow organ.

In one embodiment, the positioning attachment must be separated from theports by a distance of 0 mm or greater, preferably greater than 0.1 mm,and more preferably 1 cm. The size of the positioning device depends onthe hollow organ being ablated and ranges from 1 mm to 10 cm. In oneembodiment, the diameter of the positioning element is between 0.01 mmand 100 mm. In one embodiment, the first positioning element comprises acircular body with a diameter between 0.01 mm and 10 cm.

At step 306, the organ is ablated by automated delivery of an ablativeagent, such as steam, via infusion ports provided on the catheter. Thedelivery of the ablative agent through the infusion ports is controlledby a microprocessor coupled with the ablation device. The delivery ofablative agent is guided by predetermined programmatic instructionsdepending on the tissue to be ablated and the depth of ablationrequired. In an embodiment of the present specification where theablative agent is steam, the dose of the ablative agent is determined byconducting dosimetery study to determine the dose to ablate endometrialtissue. The variable that enables determination of total dose ofablative agent is the volume (or mass) of the tissue to be treated whichis calculated by using the length of the catheter and diameter of theorgan (for cylindrical organs). The determined dose of ablative agent isthen delivered using a micro-processor controlled steam generator.Optionally, the delivery of the ablative agent can be controlled by theoperator using predetermined dosimetry parameters.

In one embodiment, the dose is provided by first determining what thedisorder being treated is and what the desired tissue effect is, andthen finding the corresponding temperature, as shown in Tables 1 and 2,below.

TABLE 1 Temp in ° C. Tissue Effect 37-40 No significant tissue effect41-44 Reversible cell damage in few hours 45-49 Irreversible cell damageat shorter intervals 50-69 Irreversible cell damage -ablation necrosisat shorter intervals 70 Threshold temp for tissue shrinkage, H-bondbreakage 70-99 Coagulation and Hemostasis 100-200 Desiccation andCarbonization of tissue >200  Charring of tissue glucose

TABLE 2 Disorder Max. Temp in ° C. ENT/Pulmonary Nasal Polyp 60-80Turbinectomy 70-85 Bullous Disease 70-85 Lung Reduction 70-85Genitourinary Uterine Menorrhagia 80-90 Endometriosis 80-90 UterineFibroids  90-100 Benign Prostatic Hypertrophy  90-100 GastroenterologyBarrett's Esophagus 60-75 Esophageal Dysplasia 60-80 Vascular GIDisorders 55-75 Flat Polyps 60-80

In addition, the depth of ablation desired determines the holding timeat the maximum temperature. For superficial ablation (Barrett), theholding time at the maximum temperature is very short (flash burn) anddoes not allow for heat to transfer to the deeper layers. This willprevent damage to deeper normal tissue and hence prevent patientdiscomfort and complications. For deeper tissue ablation, the holdingtime at the maximum temperature will be longer, thereby allowing theheat to percolate deeper.

FIG. 4A illustrates the ablation device placed in a colon to ablate aflat colon polyp, in accordance with an embodiment of the presentspecification. The ablation catheter 10 is passed through a colonoscope40. The positioning device 11 is placed proximal, with respect to thepatient's GI tract, to a flat colonic polyp 41 which is to be ablated,in the normal colon 42. The positioning device 11 is one of aninflatable balloon, a wire mesh disc with or without an insulatedmembrane covering the disc, a cone shaped attachment, a ring shapedattachment or a freeform attachment designed to fit the colonic lumen.The positioning device 11 has the catheter 10 located toward theperiphery of the positioning device 11 placing it closer to the polyp 41targeted for non-circumferential ablation. Hence, the positioning device11 fixes the catheter to the colon 42 at a predetermined distance fromthe polyp 41 for uniform and focused delivery of the ablative agent 21.The delivery of ablative agent 21 through the infusion port 12 iscontrolled by the microprocessor 15 attached to the ablation device anddepends on tissue and the depth of ablation required. The delivery ofablative agent 21 is guided by predetermined programmatic instructionsdepending on the tissue to be ablated and the area and depth of ablationrequired. Optional infrared, electromagnetic, acoustic or radiofrequencyenergy emitters and sensors 18 are incorporated to measure the diameterof the colon. The ablation device allows for focal ablation of diseasedpolyp mucosa without damaging the normal colonic mucosa located awayfrom the catheter ports.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, ideally more than5 mm. In one embodiment, the positioning element is proximal, withrespect to the patient's GI tract, to the colon polyp. For thisapplication, the embodiment shown in FIG. 4B would be preferred.

FIG. 4B illustrates the ablation device placed in a colon 42 to ablate aflat colon polyp 41, in accordance with another embodiment of thepresent specification. As illustrated in FIG. 4B, the positioning device11 is a conical attachment at the tip of the catheter 10. The conicalattachment has a known length ‘1’ and diameter ‘d’ that is used tocalculate the amount of thermal energy needed to ablate the flat colonpolyp 41. Ablative agent 21 is directed from the infusion port 12 topolyp 41 by the positioning device 11. In one embodiment, thepositioning attachment 11 must be separated from the ablation region bya distance of greater than 0.1 mm, preferably 1 mm and more preferably 1cm. In one embodiment, the length ‘1’ is greater than 0.1 mm, preferablybetween 5 and 10 mm. In one embodiment, diameter ‘d’ depends on the sizeof the polyp and can be between 1 mm and 10 cm, preferably 1 to 5 cm.Optional infrared, electromagnetic, acoustic or radiofrequency energyemitters and sensors 18 are incorporated to measure the diameter of thecolon. This embodiment can also be used to ablate residual neoplastictissue at the edges after endoscopic snare resection of a large sessilecolon polyp.

FIG. 5A illustrates the ablation device with a coaxial catheter design,in accordance with an embodiment of the present specification. Thecoaxial design has a handle 52 a, an infusion port 53 a, an inner sheath54 a and an outer sheath 55 a. The outer sheath 55 a is used toconstrain the positioning device 56 a in the closed position andencompasses ports 57 a. FIG. 5B shows a partially deployed positioningdevice 56 b, with the ports 57 b still within the outer sheath 55 b. Thepositioning device 56 b is partially deployed by pushing the catheter 54b out of sheath 55 b.

FIG. 5C shows a completely deployed positioning device 56 c. Theinfusion ports 57 c are out of the sheath 55 c. The length ‘1’ of thecatheter 54 c that contains the infusion ports 57 c and the diameter ‘d’of the positioning element 56 c are predetermined/known and are used tocalculate the amount of thermal energy needed. FIG. 5D illustrates aconical design of the positioning element. The positioning element 56 dis conical with a known length ‘1’ and diameter ‘d’ that is used tocalculate the amount of thermal energy needed for ablation. FIG. 5Eillustrates a disc shaped design of the positioning element 56 ecomprising circumferential rings 59 e. The circumferential rings 59 eare provided at a fixed predetermined distance from the catheter 54 eand are used to estimate the diameter of a hollow organ or hollowpassage in a patient's body.

FIG. 6 illustrates an upper gastrointestinal tract with a bleedingvascular lesion being treated by the ablation device, in accordance withan embodiment of the present specification. The vascular lesion is avisible vessel 61 in the base of an ulcer 62. The ablation catheter 63is passed through the channel of an endoscope 64. The conicalpositioning element 65 is placed over the visible vessel 61. The conicalpositioning element 65 has a known length ‘1’ and diameter ‘d’, whichare used to calculate the amount of thermal energy needed forcoagulation of the visible vessel to achieve hemostasis. The conicalpositioning element has an optional insulated membrane that preventsescape of thermal energy or vapor away from the disease site.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, preferably 1 mmand more preferably 1 cm. In one embodiment, the length ‘1’ is greaterthan 0.1 mm, preferably between 5 and 10 mm. In one embodiment, diameter‘d’ depends on the size of the lesion and can be between 1 mm and 10 cm,preferably 1 to 5 cm.

FIG. 7A illustrates endometrial ablation being performed in a femaleuterus by using the ablation device, in accordance with an embodiment ofthe present specification. A cross-section of the female genital tractcomprising a vagina 70, a cervix 71, a uterus 72, an endometrium 73,fallopian tubes 74, ovaries 75 and the fundus of the uterus 76 isillustrated. A catheter 77 of the ablation device is inserted into theuterus 72 through the cervix 71 at the cervical os. In an embodiment,the catheter 77 has two positioning elements, a conical positioningelement 78 and a disc shaped positioning element 79. The positioningelement 78 is conical with an insulated membrane covering the conicalpositioning element 78. The conical element 78 positions the catheter 77in the center of the cervix 71 and the insulated membrane prevents theescape of thermal energy or ablative agent out the cervix 71 through theos. The second disc shaped positioning element 79 is deployed close tothe fundus of the uterus 76 positioning the catheter 77 in the middle ofthe cavity. An ablative agent 778 is passed through infusion ports 777for uniform delivery of the ablative agent 778 into the uterine cavity.Predetermined length ‘l’ of the ablative segment of the catheter anddiameter ‘d’ of the positioning element 79 allows for estimation of thecavity size and is used to calculate the amount of thermal energy neededto ablate the endometrial lining. In one embodiment, the positioningelements 78, 79 also act to move the endometrial tissue away from theinfusion ports 777 on the catheter 77 to allow for the delivery ofablative agent. Optional temperature sensors 7 deployed close to theendometrial surface are used to control the delivery of the ablativeagent 778. Optional topographic mapping using multiple infrared,electromagnetic, acoustic or radiofrequency energy emitters and sensorscan be used to define cavity size and shape in patients with anirregular or deformed uterine cavity due to conditions such as fibroids.Additionally, data from diagnostic testing can be used to ascertain theuterine cavity size, shape, or other characteristics.

In an embodiment, the ablative agent is vapor or steam which contractson cooling. Steam turns to water which has a lower volume as compared toa cryogen that will expand or a hot fluid used in hydrothermal ablationwhose volume stays constant. With both cryogens and hot fluids,increasing energy delivery is associated with increasing volume of theablative agent which, in turn, requires mechanisms for removing theagent, otherwise the medical provider will run into complications, suchas perforation. However, steam, on cooling, turns into water whichoccupies significantly less volume; therefore, increasing energydelivery is not associated with an increase in volume of the residualablative agent, thereby eliminating the need for continued removal. Thisfurther decreases the risk of leakage of the thermal energy via thefallopian tubes 74 or the cervix 71, thus reducing any risk of thermalinjury to adjacent healthy tissue.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, preferably 1 mmand more preferably 1 cm. In another embodiment, the positioningattachment can be in the ablated region as long as it does not cover asignificant surface area. For endometrial ablation, 100% of the tissuedoes not need to be ablated to achieve the desired therapeutic effect.

In one embodiment, the preferred distal positioning attachment is anuncovered wire mesh that is positioned proximate to the mid body region.In one embodiment, the preferred proximal positioning device is acovered wire mesh that is pulled into the cervix, centers the device,and occludes the cervix. One or more such positioning devices may behelpful to compensate for the anatomical variations in the uterus. Theproximal positioning device is preferably oval, with a long axis between0.1 mm and 10 cm (preferably 1 cm to 5 cm) and a short axis between 0.1mm and 5 cm (preferably 0.5 cm to 1 cm). The distal positioning deviceis preferably circular with a diameter between 0.1 mm and 10 cm,preferably 1 cm to 5 cm.

In another embodiment, the catheter is a coaxial catheter comprising anexternal catheter and an internal catheter wherein, upon insertion, thedistal end of the external catheter engages and stops at the cervixwhile the internal extends into the uterus until its distal end contactsthe fundus of the uterus. The length of the internal catheter that haspassed into the uterus is then used to measure the depth of the uterinecavity and determines the amount of ablative agent to use. Ablativeagent is then delivered to the uterine cavity via at least one port onthe internal catheter. In one embodiment, during treatment,intracavitary pressure within the uterus is kept below 100 mm Hg. In oneembodiment, the coaxial catheter further includes a pressure sensor tomeasure intracavitary pressure. In one embodiment, the coaxial catheterfurther includes a temperature sensor to measure intracavitarytemperature. In one embodiment, the ablative agent is steam and thesteam is released from the catheter at a pressure of less than 100 mmHg. In one embodiment, the steam is delivered with a temperature between90 and 100° C.

FIG. 7B is an illustration of a coaxial catheter 720 used in endometrialtissue ablation, in accordance with one embodiment of the presentspecification. The coaxial catheter 720 comprises an inner catheter 721and outer catheter 722. In one embodiment, the inner catheter 721 hasone or more ports 723 for the delivery of an ablative agent 724. In oneembodiment, the ablative agent is steam. In one embodiment, the outercatheter 722 has multiple fins 725 to engage the cervix to prevent theescape of vapor out of the uterus and into the vagina. In oneembodiment, the fins are composed of silicone. In one embodiment, theouter catheter 722 includes a luer lock 726 to prevent the escape ofvapor between the inner catheter 721 and outer catheter 722. In oneembodiment, the inner catheter 721 includes measurement markings 727 tomeasure the depth of insertion of the inner catheter 721 beyond the tipof the outer catheter 722. Optionally, in various embodiments, one ormore sensors 728 are incorporated into the inner catheter 721 to measureintracavitary pressure or temperature.

FIG. 7C is a flow chart listing the steps involved in an endometrialtissue ablation process using a coaxial ablation catheter, in accordancewith one embodiment of the present specification. At step 702, thecoaxial catheter is inserted into the patient's vagina and advanced tothe cervix. Then, at step 704, the coaxial catheter is advanced suchthat the fins of the outer catheter engage the cervix, effectivelystopping advancement of the outer catheter at that point. The innercatheter is then advanced, at step 706, until the distal end of theinternal catheter contacts the fundus of the uterus. The depth ofinsertion is then measured using the measurement markers on the internalcatheter at step 708, thereby determining the amount of ablative agentto use in the procedure. At step 710, the luer lock is tightened toprevent any escape of vapor between the two catheters. The vapor is thendelivered, at step 712, through the lumen of the inner catheter and intothe uterus via the delivery ports on the internal catheter to ablate theendometrial tissue.

FIG. 8 illustrates sinus ablation being performed in a nasal passage byusing the ablation device, in accordance with an embodiment of thepresent specification. A cross-section of the nasal passage and sinusescomprising nares 81, nasal passages 82, frontal sinus 83, ethmoid sinus84, and diseased sinus epithelium 85 is illustrated. The catheter 86 isinserted into the frontal sinus 83 or the ethmoid sinus 84 through thenares 81 and nasal passages 82.

In an embodiment, the catheter 86 has two positioning elements, aconical positioning element 87 and a disc shaped positioning element 88.The positioning element 87 is conical and has an insulated membranecovering. The conical element 87 positions the catheter 86 in the centerof the sinus opening 80 and the insulated membrane prevents the escapeof thermal energy or ablative agent through the opening. The second discshaped positioning element 88 is deployed in the frontal sinus cavity 83or ethmoid sinus cavity 84, positioning the catheter 86 in the middle ofeither sinus cavity. The ablative agent 8 is passed through the infusionport 89 for uniform delivery of the ablative agent 8 into the sinuscavity. The predetermined length ‘l’ of the ablative segment of thecatheter and diameter ‘d’ of the positioning element 88 allows forestimation of the sinus cavity size and is used to calculate the amountof thermal energy needed to ablate the diseased sinus epithelium 85.Optional temperature sensors 888 are deployed close to the diseasedsinus epithelium 85 to control the delivery of the ablative agent 8. Inan embodiment, the ablative agent 8 is steam which contracts on cooling.This further decreases the risk of leakage of the thermal energy thusreducing any risk of thermal injury to adjacent healthy tissue. In oneembodiment, the dimensional ranges of the positioning elements aresimilar to those in the endometrial application, with preferred maximumranges being half thereof. Optional topographic mapping using multipleinfrared, electromagnetic, acoustic or radiofrequency energy emittersand sensors can be used to define cavity size and shape in patients withan irregular or deformed nasal cavity due to conditions such as nasalpolyps.

FIG. 9 illustrates bronchial and bullous ablation being performed in apulmonary system by using the ablation device, in accordance with anembodiment of the present specification. A cross-section of thepulmonary system comprising bronchus 91, normal alveolus 92, bullouslesion 93, and a bronchial neoplasm 94 is illustrated.

In one embodiment, the catheter 96 is inserted through the channel of abronchoscope 95 into the bronchus 91 and advanced into a bullous lesion93. The catheter 96 has two positioning elements, a conical positioningelement 97 and a disc shaped positioning element 98. The positioningelement 97 is conical having an insulated membrane covering. The conicalelement 97 positions the catheter 96 in the center of the bronchus 91and the insulated membrane prevents the escape of thermal energy orablative agent through the opening into the normal bronchus. The seconddisc shaped positioning element 98 is deployed in the bullous cavity 93positioning the catheter 96 in the middle of the bullous cavity 93. Anablative agent 9 is passed through the infusion port 99 for uniformdelivery into the sinus cavity. Predetermined length ‘l’ of the ablativesegment of the catheter 96 and diameter ‘d’ of the positioning element98 allow for estimation of the bullous cavity size and is used tocalculate the amount of thermal energy needed to ablate the diseasedbullous cavity 93. Optionally, the size of the cavity can be calculatedfrom radiological evaluation using a chest CAT scan or MRI. Optionaltemperature sensors are deployed close to the surface of the bullouscavity 93 to control the delivery of the ablative agent 9. In anembodiment, the ablative agent is steam which contracts on cooling. Thisfurther decreases the risk of leakage of the thermal energy into thenormal bronchus thus reducing any risk of thermal injury to adjacentnormal tissue.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, preferably 1 mmand more preferably 1 cm. In another embodiment, the positioningattachment can be in the ablated region as long as it does not cover asignificant surface area.

In one embodiment, there are preferably two positioning attachments. Inanother embodiment, the endoscope is used as one fixation point with onepositioning element. The positioning device is between 0.1 mm and 5 cm(preferably 1 mm to 2 cm). The distal positioning device is preferablycircular with a diameter between 0.1 mm and 10 cm, preferably 1 cm to 5cm.

In another embodiment for the ablation of a bronchial neoplasm 94, thecatheter 96 is inserted through the channel of a bronchoscope 95 intothe bronchus 91 and advanced across the bronchial neoplasm 94. Thepositioning element 98 is disc shaped having an insulated membranecovering. The positioning element 98 positions the catheter in thecenter of the bronchus 91 and the insulated membrane prevents the escapeof thermal energy or ablative agent through the opening into the normalbronchus. The ablative agent 9 is passed through the infusion port 99 ina non-circumferential pattern for uniform delivery of the ablative agentto the bronchial neoplasm 94. The predetermined length ‘l’ of theablative segment of the catheter and diameter ‘d’ of the positioningelement 98 are used to calculate the amount of thermal energy needed toablate the bronchial neoplasm 94.

The catheter could be advanced to the desired location of ablation usingendoscopic, laparoscopic, stereotactic or radiological guidance.Optionally the catheter could be advanced to the desired location usingmagnetic navigation.

FIG. 10A illustrates prostate ablation being performed on an enlargedprostrate in a male urinary system by using the device, in accordancewith an embodiment of the present specification. A cross-section of amale genitourinary tract having an enlarged prostate 1001, bladder 1002,and urethra 1003 is illustrated. The urethra 1003 is compressed by theenlarged prostate 1001. The ablation catheter 1005 is passed through thecystoscope 1004 positioned in the urethra 1003 distal to theobstruction. The positioning elements 1006 are deployed to center thecatheter in the urethra 1003 and one or more insulated needles 1007 arepassed to pierce the prostate 1001. The vapor ablative agent 1008 ispassed through the insulated needles 1007 thus causing ablation of thediseased prostatic tissue resulting in shrinkage of the prostate.

The size of the enlarged prostate could be calculated by using thedifferential between the extra-prostatic and intra-prostatic urethra.Normative values could be used as baseline. Additional ports forinfusion of a cooling fluid into the urethra can be provided to preventdamage to the urethra while the ablative energy is being delivered tothe prostrate for ablation, thus preventing complications such asstricture formation.

In one embodiment, the positioning attachment must be separated from theablation region by a distance of greater than 0.1 mm, preferably 1 mm to5 mm and no more than 2 cm. In another embodiment, the positioningattachment can be deployed in the bladder and pulled back into theurethral opening/neck of the bladder thus fixing the catheter. In oneembodiment, the positioning device is between 0.1 mm and 10 cm indiameter.

FIG. 10B is an illustration of transurethral prostate ablation beingperformed on an enlarged prostrate 1001 in a male urinary system usingan ablation device, in accordance with one embodiment of the presentspecification. Also depicted in FIG. 10B are the urinary bladder 1002and prostatic urethra 1003. An ablation catheter 1023 with a handle 1020and a positioning element 1028 is inserted into the urethra 1003 andadvanced into the bladder 1002. The position element 1028 is inflatedand pulled to the junction of the bladder with the urethra, thuspositioning needles 1007 at a predetermined distance from the junction.Using a pusher 1030, the needles 1007 are then pushed out at an anglebetween 30 and 90 degree from the catheter 1023 through the urethra 1003into the prostate 1001. Vapor is administered through a port 1038 thattravels through the shaft of the catheter 1023 and exits from openings1037 in the needles 1007 into the prostatic tissue, thus ablating theprostatic tissue. In one embodiment, the needles 1007 are insulated.Optional port 1039 allows for insertion of cool fluid at a temperature<37 degree C. through opening 1040 to cool the prostatic urethra.Optional temperature sensors 1041 can be installed to detect thetemperature of the prostatic urethra and modulate the delivery of vapor.

FIG. 10C is an illustration of transurethral prostate ablation beingperformed on an enlarged prostrate 1001 in a male urinary system usingan ablation device, in accordance with another embodiment of the presentspecification. Also depicted in FIG. 10B are the urinary bladder 1002and prostatic urethra 1003. An ablation catheter 1023 with a handle 1020and a positioning element 1048 is inserted into the urethra 1003 andadvanced into the bladder 1002. The positioning element 1048 is acompressible disc that is expanded in the bladder 1002 and pulled to thejunction of the bladder with the urethra, thus positioning needles 1007at a predetermined distance from the junction. Using a pusher 1030, theneedles 1007 are then pushed out at an angle between 30 and 90 degreefrom the catheter 1023 through the urethra 1003 into the prostate 1001.Vapor is administered through a port 1038 that travels through the shaftof the catheter 1023 and exits through openings 1037 in the needles 17into the prostatic tissue, thus ablating the prostatic tissue. In oneembodiment, the needles 1007 are insulated. Optional port 1039 allowsfor insertion of cool fluid at a temperature <37 degree C. throughopening 1040 to cool the prostatic urethra. Optional temperature sensors1041 can be installed to detect the temperature of the prostatic urethraand modulate the delivery of vapor.

FIG. 10D is a flow chart listing the steps involved in a transurethralenlarged prostate ablation process using an ablation catheter, inaccordance with one embodiment of the present specification. At step1012, an ablation catheter is inserted into the urethra and advanceduntil its distal end is in the bladder. A positioning element is thendeployed on the distal end of the catheter, at step 1014, and theproximal end of the catheter is pulled so that the positioning elementabuts the junction of the bladder with the urethra, thereby positioningthe catheter shaft within the urethra. A pusher at the proximal end ofthe catheter is actuated to deploy needles from the catheter shaftthrough the urethra and into the prostatic tissue at step 1016. At step1018, an ablative agent is delivered through the needles and into theprostate to ablate the target prostatic tissue.

FIG. 10E is an illustration of transrectal prostate ablation beingperformed on an enlarged prostrate in a male urinary system using anablation device, in accordance with one embodiment of the presentspecification. Also depicted in FIG. 10E are the urinary bladder 1002and prostatic urethra 1003. The ablation device comprises a catheter1023 with a needle tip 1024. An endoscope 1022 is inserted into therectum 1021 for the visualization of the enlarged prostate 1001. Invarious embodiments, the endoscope 1022 is an echoendoscope or atransrectal ultrasound such that the endoscope can be visualized usingradiographic techniques. The catheter 1023 with needle tip 1024 ispassed through a working channel of the endoscope and transrectally intothe prostate 1001. An ablative agent is then delivered through theneedle tip 1024 into the prostatic tissue for ablation. In oneembodiment, the catheter 1023 and needle tip 1024 are composed of athermally insulated material. In various embodiments, the needle tip1024 is an echotip or sonolucent tip that can be observed usingradiologic techniques for accurate localization in the prostate tissue.In one embodiment, an optional catheter (not shown) can be placed in theurethra to insert fluid to cool the prostatic urethra 1003. In oneembodiment, the inserted fluid has a temperature less than 37° C.

FIG. 10F is an illustration of transrectal prostate ablation beingperformed on an enlarged prostrate in a male urinary system using acoaxial ablation device having a positioning element, in accordance withanother embodiment of the present specification. Also depicted in FIG.10F are the urinary bladder 1002 and prostatic urethra 1003. Theablation device comprises a coaxial catheter 1023 having an internalcatheter with a needle tip 1024 and an external catheter with apositioning element 1028. An endoscope 1022 is inserted into the rectum1021 for the visualization of the enlarged prostate 1001. In variousembodiments, the endoscope 1022 is an echoendoscope or a transrectalultrasound such that the endoscope can be visualized using radiographictechniques. The coaxial catheter 1023 with needle tip 1024 andpositioning element 1028 is passed through a working channel of theendoscope such that the positioning element 1028 comes to rest upagainst the rectal wall and the internal catheter is advancedtransrectally, thereby positioning the needle tip 1024 at apredetermined depth in the prostate 1001. In one embodiment, thepositioning element is a compressible disc that has a first, compressedpre-employment configuration and a second, expanded deployedconfiguration once it has passed beyond the distal end of the endoscope1022. An ablative agent is then delivered through the needle tip 1024into the prostatic tissue for ablation. In one embodiment, the coaxialcatheter 1023, needle tip 1024, and positioning element 1028 arecomposed of a thermally insulated material. In various embodiments, theneedle tip 1024 is an echotip or sonolucent tip that can be observedusing radiologic techniques for accurate localization in the prostatetissue. In one embodiment, an optional catheter (not shown) can beplaced in the urethra to insert fluid to cool the prostatic urethra1003. In one embodiment, the inserted fluid has a temperature less than37° C.

FIG. 10G is a flow chart listing the steps involved in a transrectalenlarged prostate ablation process using an ablation catheter, inaccordance with one embodiment of the present specification. At step1042, an endoscope is inserted into the rectum of a patient forvisualization of the prostate. A catheter with a needle tip is thenadvanced, at step 1044, through a working channel of the endoscope andthrough the rectal wall and into the prostate. Radiologic methods areused to guide the needle into the target prostatic tissue at step 1046.At step 1048, an ablative agent is delivered through the needle and intothe prostate to ablate the target prostatic tissue.

FIG. 10H is an illustration of an ablation catheter 1050 for permanentimplantation in the body to deliver repeat ablation and FIG. 10I is atrocar 1056 used to place the ablation catheter 1050 in the body. FIG.10J is an illustration of the catheter 1050 of FIG. 10H and trocar 1056of FIG. 10I assembled for placement of the catheter 1050 into tissuetargeted for ablation in the human body. The catheter 1050 of FIG. 10Hhas an anchoring unit 1054, a shaft 1055 and a port 1057. The anchoringunit 1054 anchors the catheter 1050 in the tissue targeted for ablationand houses one or more openings 1059 for the exit of the ablative agent.Port 1057 resides in the subcutaneous tissue or at a site that is easilyaccessible for repeat ablation. An ablative agent is introduced into theport 1057 and travels through the shaft 1055 to the site for ablationand exits through the one or more openings 1059 in the anchoring unit1054. As illustrated in FIG. 10J, in the assembled configuration 1053,the trocar 1056 locks with the catheter 1050 and straightens theanchoring unit 1054 for easy placement of the catheter 1050.Alternatively, in one embodiment (not pictured), the anchoring unit is aballoon that is inflated to anchor the device in the desired tissue. Thesubcutaneous port 1057, in a manner similar to a subcutaneous port forchemotherapy, can be easily accessed using an insulated needle orcatheter for delivery of ablative agent for multiple repeat ablationsover time. The port 1057 obviates the need for repeat invasiveprocedures and the cost of catheter placement into the tissue forablation.

FIG. 11 illustrates fibroid ablation being performed in a female uterusby using the ablation device, in accordance with an embodiment of thepresent specification. A cross-section of a female genitourinary tractcomprising a uterine fibroid 1111, uterus 1112, and cervix 1113 isillustrated. The ablation catheter 1115 is passed through thehysteroscope 1114 positioned in the uterus distal to the fibroid 1111.The ablation catheter 1115 has a puncturing tip 1120 that helps punctureinto the fibroid 1111. The positioning elements 1116 are deployed tocenter the catheter in the fibroid and insulated needles 1117 are passedto pierce the fibroid tissue 1111. The vapor ablative agent 1118 ispassed through the needles 1117 thus causing ablation of the uterinefibroid 1111 resulting in shrinkage of the fibroid.

FIG. 12A illustrates a blood vessel ablation 1240 being performed by anablation device, in accordance with one embodiment of the presentspecification. The ablation involves replacing the blood within thevessel with a conductive medium used to distribute and conduct anablative agent in the vessel. In one embodiment, the device used for theablation comprises a catheter 1220 with a distal end and a proximal end.The distal end of the catheter 1220 is provided with at least one port1222 used to remove blood from the vessel 1240, at least one other port1224 for injecting a conductive medium into the vessel 1240, and atleast one other port for delivering an ablative agent 1226 into thevessel 1240. In various embodiments, each port or any combination ofports is capable of removing blood, injecting a conductive medium,and/or delivering an ablative agent, as discussed with reference to theablation catheter of FIG. 2F. In one embodiment, the conductive mediumis water. In another embodiment, the conductive medium is saline. In oneembodiment, the ablative agent is steam. The proximal end of thecatheter 1220 is coupled to at least one source to provide suction, theconductive medium, and the ablative agent. In one embodiment, thecatheter 1220 further includes a sensor 1227 wherein measurementsprovided by said sensor are used to control the flow of the ablativeagent. In various embodiments, the sensor is configured to sense any oneor combination of blood flow and ablation parameter, including flow ofablative agent, temperature, and pressure.

In one embodiment, a first means for occluding blood flow is appliedproximally to the insertion point of the catheter into the blood vessel.In one embodiment, the first means comprises a tourniquet (not shown).In another embodiment, the first means comprises an intraluminalocclusive element 1228. In one embodiment, the intraluminal occlusiveelement 1228 includes a unidirectional valve 1229 to permit the flow ofblood into the ablation area and to restrict the flow of conductivemedium or ablative agent out of the ablation area. In one embodiment, asecond means for occluding blood flow is applied distally from theinsertion point of the catheter into the blood vessel. The second meansfor occluding blood flow acts to prevent blood flow back into theablation area and also prevents the passage of conductive medium andablative agent beyond the ablation area. In one embodiment, the secondmeans comprises a tourniquet. In another embodiment, the second meanscomprises a second intraluminal occlusive element. In one embodiment,the second intraluminal occlusive element includes a unidirectionalvalve to permit the flow of blood into the ablation area and to restrictthe flow of conductive medium or ablative agent out of the ablationarea.

FIG. 12B illustrates a blood vessel 1240 ablation being performed by anablation device, in accordance with another embodiment of the presentspecification. The ablation device is a coaxial catheter 1230 comprisingan internal catheter 1232 and an external catheter 1234. In oneembodiment, the internal catheter has a distal end with ports 1233 thatfunction in the same manner as those on the catheter of FIG. 12A and aproximal end coupled to a source in the same manner as the catheter ofFIG. 12A. The external catheter 1234 is composed of an insulatedmaterial and functions as an insulating sheath over the internalcatheter 1232. In the embodiment pictured in FIG. 12B, the deviceincludes at least one intraluminal occlusive device 1238 with aunidirectional valve 1239, coupled to the external catheter 1234 andpositioned proximally, with respect to blood flow, to the ablationdevice. The intraluminal occlusive device 1238 functions in the samemanner as that referenced with respect to FIG. 12A. In anotherembodiment, the intraluminal occlusive device is not coupled to theexternal catheter. In another embodiment, an additional intraluminaldevice is positioned distally from the ablation catheter. In variousother embodiments, the flow of blood is stopped by the application of atleast one tourniquet positioned proximally or distally from the ablationdevice, or a plurality of tourniquets positioned both proximally anddistally from the ablation device. In one embodiment, the internalcatheter 1232 further includes a sensor 1237 wherein measurementsprovided by said sensor are used to control the flow of the ablativeagent. In various embodiments, the sensor is configured to sense any oneor combination of blood flow and ablation parameter, including flow ofablative agent, temperature, and pressure.

FIG. 12C is a flow chart listing the steps involved in a blood vesselablation process using an ablation catheter, in accordance with oneembodiment of the present specification. At step 1202, a catheter isinserted into a patient and advanced to the target blood vessel. Theflow of blood into the target vessel is stopped at step 1204. Thecatheter tip is then inserted into the target vessel at step 1206. Atstep 1208, suction is applied to the catheter to remove blood from thetarget vessel. A conductive medium is then injected into the targetvessel through ports on the catheter at step 1210. Then, at step 1212,an ablative agent is delivered into the conductive medium to ablate thetarget vessel. Suction is applied to the catheter at step 1214 to removethe conductive medium and ablative agent.

FIG. 13A illustrates a cyst ablation being performed by an ablationdevice, in accordance with one embodiment of the present specification.The device comprises an ablation catheter 1320 similar to thosedescribed with reference to FIGS. 2D-2F. The catheter 1320 is insertedinto the cyst 1340 and the contents of the cyst are removed via suctionthrough the ports 1333 at the distal end of the catheter 1320. Aconductive medium 1324 is then injected into the cyst 1340, followed bythe delivery of an ablative agent 1325 to ablate the cyst. In oneembodiment, the catheter 1320 includes a sensor 1328 whereinmeasurements provided by said sensor are used to control the flow of theablative agent. In one embodiment, the catheter includes echogenicelements to assist with the placement of the catheter into the cystunder ultrasonic guidance. In another embodiment, the catheter includesradio-opaque elements to assist with the placement of the catheter intothe cyst under radiologic guidance.

FIG. 13B is a flow chart listing the steps involved in a cyst ablationprocess using an ablation catheter, in accordance with one embodiment ofthe present specification. At step 1302, a catheter is inserted into apatient and advanced to the target cyst. The catheter tip is theninserted into the target cyst at step 1304. At step 1306, suction isapplied to the catheter to remove at least a portion of the contents ofthe target cyst. A conductive medium is then injected into the targetcyst through ports on the catheter at step 1308. Then, at step 1310, anablative agent is delivered into the conductive medium to ablate thetarget cyst. Suction is applied to the catheter at step 1312 to removethe conductive medium and ablative agent.

FIG. 14 is a flow chart listing the steps involved in a solid tumorablation process using an ablation catheter, in accordance with oneembodiment of the present specification. At step 1402, a catheter isinserted into a patient and advanced to the target tumor. The cathetertip is then inserted into the target tumor at step 1404. A conductivemedium is injected into the target tumor through ports on the catheterat step 1406. Then, at step 1408, an ablative agent is delivered intothe conductive medium to ablate the target tumor. In one embodiment, thecatheter includes a sensor wherein measurements provided by said sensorare used to control the flow of the ablative agent. In one embodiment,the catheter includes echogenic elements to assist with the placement ofthe catheter into the tumor under ultrasonic guidance. In anotherembodiment, the catheter includes radio-opaque elements to assist withthe placement of the catheter into the tumor under radiologic guidance.

FIG. 15A illustrates a non-endoscopic device 1520 used for internalhemorrhoid ablation, in accordance with one embodiment of the presentspecification. The device 1520 is inserted into the rectum of a patientto selectively ablate internal hemorrhoids. The device 1520 includes apiston 1521 that, when pulled down, creates suction in a chamber or slot1522 within the device 1520. The suction draws a portion of rectaltissue with a hemorrhoid into the chamber 1522. A port 1524 on thedevice 1520 is used to provide an ablative agent 1525 to the chamber1522 to ablate the hemorrhoid. In one embodiment, the device is composedof a thermally insulated material to avoid the transfer of ablativeenergy to the surrounding rectal mucosa. In one embodiment, the ablativeagent is steam.

FIG. 15B is a flow chart listing the steps involved in an internalhemorrhoid ablation process using a non-endoscopic ablation device, inaccordance with one embodiment of the present specification. At step1502, the device described with reference to FIG. 15A is inserted intothe rectum of a patient with internal hemorrhoids. A piston on thedevice is actuated to create suction and draw a portion of hemorrhoidtissue into a slot in the device at step 1504. Then, at step 1506, anablative agent is delivered into the slot via a port on the device toablate the hemorrhoid. The piston is released at step 1508 to removesuction, thereby releasing the portion of rectal tissue.

FIG. 16A illustrates an endoscopic device 1620 used for internalhemorrhoid ablation, in accordance with one embodiment of the presentspecification. In one embodiment, the device 1620 is composed of athermally insulated, transparent material. The device 1620 is mounted tothe distal end of an endoscope 1630 and both are inserted into thepatient's rectum. Suction is applied to the endoscope 1630, drawing aportion of rectal tissue with a hemorrhoid into a chamber or slot 1622in the device 1620.

In one embodiment, an ablative agent 1625 is delivered to the chamber orslot 1622 through a port 1624 in the device 1620. In another embodiment,a needle (not shown) is advanced through the port 1624 and inserted intothe rectal submucosa at the position of the hemorrhoid. An ablativeagent is then injected directly into the hemorrhoid through the needlefor selective hemorrhoid ablation.

FIG. 16B is a flow chart listing the steps involved in an internalhemorrhoid ablation process using an endoscopic ablation device, inaccordance with one embodiment of the present specification. At step1602, an endoscope with an ablation device coupled to its distal end isinserted into the rectum of a patient with internal hemorrhoids. At step1604, suction is applied to the endoscope to draw a portion of rectaltissue with a hemorrhoid into a chamber in the device.

In one embodiment, at step 1606, an ablative agent is delivered througha port on the device into the chamber to ablate the hemorrhoid. Suctionis then removed from the endoscope at step 1608 to release the portionof rectal tissue.

In another embodiment, at step 1610, a needle is advanced through theport on the device, through the chamber, and into the hemorrhoid. Anablative agent is then injected at step 1612 through the needle into thehemorrhoid to ablate said hemorrhoid. At step 1614, the needle isremoved from the hemorrhoid. Suction is then removed from the endoscopeat step 1616 to release the portion of rectal tissue.

FIG. 17A illustrates a stent 1720 used to provide localized ablation toa target tissue, in accordance with one embodiment of the presentspecification. Similar to conventional stents, the ablation stent 1720of the present specification has a compressed, pre-deploymentconfiguration and an expanded, post-deployment configuration. Thepre-deployment configuration assists with delivery of the stent and thepost-deployment configuration helps to keep the stent positionedcorrectly. The stent 1720 is covered with a conductive membrane 1722that conducts an ablative agent or ablative energy from within the stentlumen to the external surface of the stent, resulting in ablation of thetissue in contact with the stent 1720. In one embodiment, the membrane1722 includes at least one opening 1723 for the transfer of an ablativeagent 1724 from the stent lumen to the surrounding tissue. In oneembodiment, the stent 1720 is composed of a wire mesh. In oneembodiment, the membrane 1722 is composed of a thermally conductivematerial. In one embodiment, the membrane is composed of silicone. Inone embodiment, the membrane 1722 comprises a plurality of individualoverlapping membranes attached to the stent with intervening unattachedareas through which the ablative agent can escape from the stent lumeninto the surrounding tissues. The unattached portions of the membrane1722 act as a unidirectional flap valve allowing for ablative agent toexit the stent lumen but preventing the ingrowth of tumor or tissue intothe stent 1720.

FIG. 17B illustrates a catheter 1730 used to deploy, and provide anablative agent to, the stent of FIG. 17A. The catheter 1730 has aproximal end and a distal end with a shaft 1731 having a lumentherebetween. In one embodiment, the catheter 1730 is composed of athermally insulated material. The ablative agent 1733 enters the lumenof the catheter from the proximal end 1732. The catheter 1730 has one ormore openings 1735 at the distal end that allow for the ablative agent1733 to exit the catheter shaft 1731 and enter the stent lumen. Invarious embodiments, the catheter shaft 1731 has one or more positioningelements 1734 to position the at least one opening 1735 at a desiredlocation inside the stent lumen. These positioning elements 1734 alsoact as occlusive elements to prevent the passage of ablative agent intothe adjacent normal tissue. In various embodiments, optional lumens areavailable for the passage of a guidewire or injection of radiologiccontrast material.

FIG. 17C illustrates the stent 1720 of FIG. 17A working in conjunctionwith the catheter 1730 of FIG. 17B. Ablative agent 1733 is provided tothe proximal end 1732 of the catheter 1730 and travels through thecatheter shaft 1731 to the distal end of the catheter 1730. The ablativeagent 1733 exits the catheter 1730 through the openings 1735 at thedistal end of the catheter 1730. The ablative agent 1733 is transferredto the surrounding tissues via the conductive membrane on the stent1720. The positioning elements 1734 prevent the escape of ablative agent1733 from the proximal and distal ends of the stent 1720.

FIG. 17D illustrates the stent of FIG. 17A and the catheter of FIG. 17Bpositioned in a bile duct 1741 obstructed by a pancreatic tumor 1740. Astent 1720 is placed in the bile duct to open the obstruction. The stent1720 has a thermally conducting membrane 1722 that allows for transferof ablative energy from inside the stent lumen to the surroundingtissue. In one embodiment, the membrane 1722 has openings to allow forthe passage of the ablative agents from inside the stent lumen to thesurrounding tissue. The catheter 1730 is used to deliver the catheter atinitial deployment and to deliver ablative agent. The catheter 1730 isalso used for subsequent ablation in an already deployed stent 1720. Theablative agent 1733 is delivered to the lumen of the stent through atleast one opening 1735 in the catheter shaft. The ablative agent thendelivers the ablative energy from the ablative agent 1733 through thethermally conducting membrane 1724 or allows for passage of the ablativeagent 1733 through the openings into the surrounding tissue to ablatethe tumor 1740. The catheter has a first positioning element 1734 at thedistal end to position the catheter at a fixed distance from the distalend of the stent 1720. This positioning element is also used anocclusive member to prevent the flow of the ablative agent 1733 outsidethe lumen of the stent into the normal healthy tissue of the bile duct1741. In one embodiment, the catheter has a second positioning element1735 at the proximal end of the stent serving similar function as thefirst positioning element 1734.

FIG. 17E is a flow chart listing the steps involved in a hollow tissueor organ ablation process using an ablation stent and catheter, inaccordance with one embodiment of the present specification. At step1702, the catheter with the ablation stent coupled to its distal end isinserted into a hollow tissue of a patient. The catheter is thenadvanced at step 1704 to the target lesion and the stent is deployed. Atstep 1706, ablative agent is delivered to the stent lumen via ports onthe catheter. The ablative agent or energy is then conducted to thesurrounding tissue via the conductive membrane on the stent. Onceablation is completed, the catheter is removed from the patient at step1708. If further ablation is needed, the catheter is re-inserted at step1710 and advanced to the location of the stent. Ablation is thenre-performed at step 1706.

FIG. 18 illustrates a vapor delivery system using an RF heater forsupplying vapor to the ablation device, in accordance with an embodimentof the present specification. In an embodiment, the vapor is used as anablative agent in conjunction with the ablation device described in thepresent specification. RF heater 64 is located proximate a pressurevessel 42 containing a liquid 44. RF heater 64 heats vessel 42, in turnheating the liquid 44. The liquid 44 heats up and begins to evaporatecausing an increase in pressure inside the vessel 42. The pressureinside vessel 42 can be kept fairly constant by providing a thermalswitch 46 that controls resistive heater 64. Once the temperature of theliquid 44 reaches a predetermined temperature, the thermal switch 46shuts off RF heater 64. The vapor created in pressure vessel 42 may bereleased via a control valve 50. As the vapor exits vessel 42, apressure drop is created in the vessel resulting in a reduction intemperature. The reduction of temperature is measured by thermal switch46, and RF heater 64 is turned back on to heat liquid 44. In oneembodiment, the target temperature of vessel 42 may be set toapproximately 108° C., providing a continuous supply of vapor. As thevapor is released, it undergoes a pressure drop, which reduces thetemperature of the vapor to a range of approximately 90-100° C. Asliquid 44 in vessel 42 evaporates and the vapor exits vessel 42, theamount of liquid 44 slowly diminishes. The vessel 42 is optionallyconnected to reservoir 43 containing liquid 44 via a pump 49 which canbe turned on by the controller 24 upon sensing a fall in pressure ortemperature in vessel 42, delivering additional liquid 44 to the vessel42.

Vapor delivery catheter 16 is connected to vessel 42 via a fluidconnector 56. When control valve 50 is open, vessel 42 is in fluidcommunication with delivery catheter 16 via connector 56. Control switch60 may serve to turn vapor delivery on and off via actuator 48. Forexample, control switch 60 may physically open and close the valve 50,via actuator 48, to control delivery of vapor stream from the vessel 42.Switch 60 may be configured to control other attributes of the vaporsuch as direction, flow, pressure, volume, spray diameter, or otherparameters.

Instead of, or in addition to, physically controlling attributes of thevapor, switch 60 may electrically communicate with a controller 24.Controller 24 controls the RF heater 64, which in turn controlsattributes of the vapor, in response to actuation of switch 60 by theoperator. In addition, controller 24 may control valves temperature orpressure regulators associated with catheter 16 or vessel 42. A flowmeter 52 may be used to measure the flow, pressure, or volume of vapordelivery via the catheter 16. The controller 24 controls the temperatureand pressure in the vessel 42 and the time, rate, flow, and volume ofvapor flow through the control valve 50. These parameters are set by theoperator 11. The pressure created in vessel 42, using the targettemperature of 108° C., may be in the order of 25 pounds per square inch(psi) (1.72 bars).

FIG. 19 illustrates a vapor delivery system using a resistive heater forsupplying vapor to the ablation device, in accordance with an embodimentof the present specification. In an embodiment, the generated vapor isused as an ablative agent in conjunction with the ablation devicedescribed in the present specification. Resistive heater 40 is locatedproximate a pressure vessel 42. Vessel 42 contains a liquid 44.Resistive heater 40 heats vessel 42, in turn heating liquid 44.Accordingly, liquid 44 heats and begins to evaporate. As liquid 44begins to evaporate, the vapor inside vessel 42 causes an increase inpressure in the vessel. The pressure in vessel 42 can be kept fairlyconstant by providing a thermal switch 46 that controls resistive heater40. When the temperature of liquid 44 reaches a predeterminedtemperature, thermal switch 46 shuts off resistive heater 40. The vaporcreated in pressure vessel 42 may be released via a control valve 50. Asthe vapor exits vessel 42, vessel 42 experiences a pressure drop. Thepressure drop of vessel 42 results in a reduction of temperature. Thereduction of temperature is measured by thermal switch 46, and resistiveheater 40 is turned back on to heat liquid 44. In one embodiment, thetarget temperature of vessel 42 may be set to approximately 108° C.,providing a continuous supply of vapor. As the vapor is released, itundergoes a pressure drop, which reduces the temperature of the vapor toa range of approximately 90-100° C. As liquid 44 in vessel 42 evaporatesand the vapor exits vessel 42, the amount of liquid 44 slowlydiminishes. The vessel 42 is connected to another vessel 43 containingliquid 44 via a pump 49 which can be turned on by the controller 24 uponsensing a fall in pressure or temperature in vessel 42 deliveringadditional liquid 44 to the vessel 42.

Vapor delivery catheter 16 is connected to vessel 42 via a fluidconnector 56. When control valve 50 is open, vessel 42 is in fluidcommunication with delivery catheter 16 via connector 56. Control switch60 may serve to turn vapor delivery on and off via actuator 48. Forexample, control switch 60 may physically open and close the valve 50,via actuator 48, to control delivery of vapor stream from the vessel 42.Switch 60 may be configured to control other attributes of the vaporsuch as direction, flow, pressure, volume, spray diameter, or otherparameters. Instead of, or in addition to, physically controllingattributes of the vapor, switch 60 may electrically communicate with acontroller 24. Controller 24 controls the resistive heater 40, which inturn controls attributes of the vapor, in response to actuation ofswitch 60 by the operator. In addition, controller 24 may control valvestemperature or pressure regulators associated with catheter 16 or vessel42. A flow meter 52 may be used to measure the flow, pressure, or volumeof vapor delivery via the catheter 16. The controller 24 controls thetemperature and pressure in the vessel 42 as well as time, rate, flow,and volume of vapor flow through the control valve 50. These parametersare set by the operator 11. The pressure created in vessel 42, using thetarget temperature of 108° C., may be on the order of 25 pounds persquare inch (psi) (1.72 bars).

FIG. 20 illustrates a vapor delivery system using a heating coil forsupplying vapor to the ablation device, in accordance with an embodimentof the present specification. In an embodiment, the generated vapor isused as an ablative agent in conjunction with the ablation devicedescribed in the present specification. The vapor delivery systemincludes a conventional generator 2000 that is commonly used inoperating rooms to provide power to specialized tools, i.e., cutters.The generator 2000 is modified to include an integrated liquid reservoir2001. In one embodiment, the reservoir 2001 is filled with roomtemperature pure water. The reservoir 2001 portion of the generator 2000is connected to the heating component 2005 via a reusable active cord2003. In one embodiment, the reusable active cord 2003 may be used up to200 times. The cord 2003 is fixedly attached via connections at bothends to withstand operational pressures, and preferably a maximumpressure, such that the cord does not become disconnected. In oneembodiment, the connections can resist at least 1 atm of pressure. Inone embodiment, the connections are of a luer lock type. The cord 2003has a lumen through which liquid flows to the heating component 2005. Inone embodiment, the heating component 2005 contains a coiled length oftubing 2006. As liquid flows through the coiled tubing 2006, it isheated by the surrounding heating component 2005 in a fashion similar toa conventional heat exchanger. As the liquid is heated, it becomesvaporized. The heating component contains a connector 2007 thataccommodates the outlet of vapor from the coiled tubing 2006. One end ofa single use cord 2008 attaches to the heating component 2005 at theconnector 2007. The connector 2007 is designed to withstand pressuresgenerated by the vapor inside the coiled tubing 2006 during operation.In one embodiment, the connector 2007 is of a luer lock type. Anablation device 2009 is attached to the other end of the single use cord2008 via a connection able to withstand the pressures generated by thesystem. In one embodiment, the ablation device is integrated with acatheter. In another embodiment, the ablation device is integrated witha probe. The single use cord 2008 has a specific luminal diameter and isof a specific length to ensure that the contained vapor does notcondense into liquid while simultaneously providing the user enoughslack to operate. In addition, the single use cord 2008 providessufficient insulation so that personnel will not suffer burns whencoming into contact with the cord. In one embodiment, the single usecord has a luminal diameter of less than 3 mm, preferably less than 2.6mm, and is longer than 1 meter in length.

In one embodiment, the system includes a foot pedal 2002 by which theuser can supply more vapor to the ablation device. Depressing the footpedal 2002 allows liquid to flow from the reservoir 2001 into theheating component 2005 where it changes into vapor within the coiledtubing 2006. The vapor then flows to the ablation device via the singleuse tube 2008. The ablation device includes an actuator by which theuser can open small ports on the device, releasing the vapor andablating the target tissue.

FIG. 21 illustrates the heating component 2105 and coiled tubing 2106 ofthe heating coil vapor delivery system of FIG. 20, in accordance with anembodiment of the present specification. Liquid arrives through areusable active cord (not shown) at a connection 2102 on one side of theheating component 2105. The liquid then travels through the coiledtubing 2106 within the heating component 2105. The coiled tubing iscomposed of a material and configured specifically to provide optimalheat transfer to the liquid. In one embodiment, the coiled tubing 2106is copper. The temperature of the heating component 2105 is set to arange so that the liquid is converted to vapor as it passes through thecoiled tubing 2106. In one embodiment, the temperature of the heatingcomponent 2105 can be set by the user through the use of a temperaturesetting dial 2108. In one embodiment, the heating component contains anon/off switch 2109 and is powered through the use of an attached ACpower cord 2103. In another embodiment, the heating component receivespower through an electrical connection integrated into and/orfacilitated by the active cord connection to the reservoir. The vaporpasses through the end of the coiled tubing 2106 and out of the heatingcomponent 2105 through a connector 2107. In one embodiment, theconnector 2107 is located on the opposite side of the heating component2105 from the inlet connection 2102. A single use cord (not shown)attaches to the connector 2107 and supplies vapor to the ablationdevice.

FIG. 22A illustrates the unassembled interface connection between theablation device 2208 and the single use cord 2201 of the heating coilvapor delivery system of FIG. 20, in accordance with an embodiment ofthe present specification. In this embodiment, the ablation device 2208and single use cord 2201 are connected via a male-to-male double luerlock adapter 2205. The end of the single use cord 2201 is threaded toform a female end 2202 of a luer lock interface and connects to one endof the adapter 2205. The ablation device 2208 includes a smallprotrusion at its non-operational end which is also threaded to form afemale end 2207 of a luer lock interface and connects to the other endof the adapter 2205. The threading luer lock interface provides a secureconnection and is able to withstand the pressures generated by theheating coil vapor delivery system without becoming disconnected.

FIG. 22B illustrates the assembled interface connection between theablation device 2208 and the single use cord 2201 of the heating coilvapor delivery system of FIG. 20, in accordance with an embodiment ofthe present specification. The male-to-male double luer lock adapter2205 is pictured securing the two components together. The double luerlock interface provides a stable seal, allows interchangeability betweenablation devices, and enables users to quickly replace single use cords.

FIG. 23 illustrates a vapor ablation system using a heater or heatexchange unit for supplying vapor to the ablation device, in accordancewith another embodiment of the present specification. In the picturedembodiment, water for conversion to vapor is supplied in a disposable,single use sterile fluid container 2305. The container 2305 is sealedwith a sterile screw top 2310 that is punctured by a needle connector2315 provided on a first end of a first filter member 2320. The secondend of the first filter member 2320, opposite the first end, isconnected to a pump 2325 for drawing the water from the fluid container2305, through the first filter member 2320, and into the heater or heatexchange unit 2330. The system includes a microcontroller ormicroprocessor 2335 for controlling the actions of the pump 2325 andheater or heat exchange unit 2330. The heater or heat exchange unit 2330converts the water into vapor (steam). The increase in pressuregenerated during the heating step drives the vapor through an optionalsecond filter member 2340 and into the ablation catheter 2350. In oneembodiment, the heater or heat exchange unit 2330 includes a one-wayvalve at its proximal end to prevent the passage of vapor back towardthe pump 2325. In various embodiments, optional sensors 2345 positionedproximate the distal end of the catheter 2350 measure one or more oftemperature, pressure, or flow of vapor and transmit the information tothe microcontroller 2335, which in turn controls the rate of the pump2325 and the level of vaporizing energy provided by the heater or heatexchange unit 2330.

FIG. 24 illustrates the fluid container 2405, first filter member 2420,and pump 2425 of the vapor ablation system of FIG. 23. As can be seen inthe pictured embodiment, the system includes a water-filled, disposable,single use sterile fluid container 2405 and a pump 2425 with a firstfilter member 2420 disposed therebetween. The first filter member 2420is connected to the container 2405 and pump 2425 by two first and secondlengths of sterile tubing 2407, 2422 respectively, and includes a filterfor purifying the water used in the ablation system.

FIGS. 25 and 26 illustrate first and second views respectively, of thefluid container 2505, 2605, first filter member 2520, 2620, pump 2525,2625, heater or heat exchange unit 2530, 2630, and microcontroller 2535,2635 of the vapor ablation system of FIG. 23. The container 2505, 2605is connected to the first filter member 2520, 2620 by a first length ofsterile tubing 2507, 2607 and the first filter member 2520, 2620 isconnected to the pump 2525, 2625 by a second length of sterile tubing2522, 2622. A third length of sterile tubing 2527, 2627 connects thepump 2525, 2625 to the heater or heat exchange unit 2530, 2630. Themicrocontroller 2535, 2635, is operably connected to the pump 2525, 2625by a first set of control wires 2528, 2628 and to the heater or heatexchange unit 2530, 2630 by a second set of control wires 2529, 2629.The arrows 2501, 2601 depict the direction of the flow of water from thecontainer 2505, 2605, through the first filter member 2520, 2620 andpump 2525, 2625 and into the heater or heat exchange member 2530, 2630where it is converted to vapor. Arrow 2531, 2631 depicts the directionof flow of vapor from the heater or heat exchange unit 2530, 2630 intothe ablation catheter (not shown) for use in the ablation procedure.

FIG. 27 illustrates the unassembled first filter member 2720 of thevapor ablation system of FIG. 23, depicting the filter 2722 positionedwithin. In one embodiment, the first filter member 2720 includes aproximal portion 2721, a distal portion 2723, and a filter 2722. Theproximal portion 2721 and distal portion 2723 secure together and holdthe filter 2722 within. Also depicted in FIG. 27 are the disposable,single use sterile fluid container 2705 and the first length of steriletubing 2707 connecting the container 2705 to the proximal portion 2721of the first filter member 2720.

FIG. 28 illustrates one embodiment of the microcontroller 2800 of thevapor ablation system of FIG. 23. In various embodiments, themicrocontroller 2800 includes a plurality of control wires 2828connected to the pump and heater or heat exchange unit for controllingsaid components and a plurality of transmission wires 2847 for receivingflow, pressure, and temperature information from optional sensorspositioned proximate the distal end of the ablation catheter.

FIG. 29 illustrates one embodiment of a catheter assembly 2950 for usewith the vapor ablation system of FIG. 23. Vapor is delivered from theheater or heat exchange unit to the catheter assembly 2950 via a tube2948 attached to the proximal end of a connector component 2952 of theassembly 2950. A disposable catheter 2956 with a fixedly attacheddisposable length of flexible tubing 2958 at its distal end is fittedover the connector component 2952. A second filter member 2954 ispositioned between the connector component 2952 and the disposablecatheter 2956 for purifying the vapor supplied by the heater or heatexchange unit. The connector component 2952 includes two washers 2953positioned apart a short distance at its distal end to engage theoverlaying disposable catheter 2956 and form a double-stage seal,thereby preventing vapor leakage between the components. Once thedisposable catheter 2956 has been fitted to the distal end of theconnector component 2952, a catheter connector 2957 is slid over thedisposable flexible tubing 2958 and disposable catheter 2956 and is thensnapped into place onto the connector component 2952. The catheterconnector 2957 acts to keep the disposable catheter 2956 in place andalso assists in preventing vapor leakage. In various embodiments, thedisposable flexible tubing 2958 includes one or more holes or ports 2959at or proximate its distal end for the delivery of ablative vapor totarget tissues.

FIG. 30 illustrates one embodiment of a heat exchange unit 3030 for usewith the vapor ablation system of FIG. 23. The heat exchange unit 3030comprises a length of coiled tubing 3035 surrounded by a heating element3034. Water 3032 enters the coiled tubing 3035 of the heat exchange unit3030 at an entrance port 3033 proximate a first end of said heatexchange unit 3030. As the water 3032 flows within the coiled tubing3035, it is converted into vapor (steam) 3038 by the heat emanating fromsaid coiled tubing 3035 which has been heated by the heating element3034. The vapor 3038 exits the coiled tubing 3035 of the heat exchangeunit 3030 at an exit port 3037 proximate a second end of said heatexchange unit 3030 and is then delivered to the ablation catheter (notshown) for use in the ablation procedure.

FIG. 31A illustrates another embodiment of a heat exchange unit 3160 foruse with the vapor ablation system of the present specification. In thepictured embodiment, the heat exchange unit 3160 comprises acylindrically shaped, pen sized ‘clamshell’ style heating block. Theheating block of the heat exchange unit 3160 includes a first half 3161and a second half 3162 fixedly attached by a hinge 3163 along one side,wherein the halves 3161, 3162 fold together and connect on the oppositeside. In one embodiment, the sides of the halves opposite the sides withthe hinge include a clasp for holding the two halves together. In oneembodiment, one of the halves includes a handle 3164 for manipulatingthe heat exchange unit 3160. When the halves are folded together, theheat exchange unit 3160 snugly envelopes a cylindrically shaped catheterfluid heating chamber 3151 attached to, inline and in fluidcommunication with, the proximal end of the ablation catheter 3150. Eachhalf 3161, 3162 of the heat exchange unit 3160 includes a plurality ofheating elements 3165 for heating the block. In various embodiments,heat is transferred from the heating elements 3165 to the catheter fluidheating chamber 3151 using resistive or RF heating. The positioning andfit of the heating block place it in close thermal contact with thecatheter fluid heating chamber 3151. When in operation, the heatingelements 3165 heat the heating block which transfers heat to thecatheter fluid heating chamber 3151, which in turn heats the waterinside the chamber 3151, converting said water to vapor. The heatingblock does not directly contact the water. In one embodiment, thecatheter fluid heating chamber 3151 comprises a plurality of linearindentations 3191 stretching along the length of the component and inparallel with the heating elements 3165. Upon closing the halves 3161,3162, the heating elements 3165, which optionally protrude from theinternal surfaces of the halves 3161, 3162 contact, and fit within, thelinear indentations 3191. This also increases the surface area ofcontact between the heating block and the heating chamber, improving theefficiency of heat exchange.

A luer fitting coupler 3149 is provided at the proximal end of thecatheter fluid heating chamber 3151 for connecting a tube supplyingsterile water. In one embodiment, a one-way valve is included at theproximal end of the catheter fluid heating chamber 3151, distal to theluer fitting 3149, to prevent the passage of vapor under pressure towardthe water supply.

FIG. 31B illustrates another embodiment of a heat exchange unit 3170 foruse with the vapor ablation system of the present specification. Theheat exchange unit 3170 of FIG. 31B functions similarly to the heatexchange unit 3160 pictured in FIG. 31A. However, rather than having anopen design capable of opening and closing, heat exchange unit 3170 hasa closed design and is configured to slide over the catheter fluidheating chamber 3151. In one embodiment, the heat exchange unit 3170includes a handle 3174 for manipulation of said unit about the catheter3150.

As described above, the catheter fluid heating chamber is designed aspart of the ablation catheter and, along with the remainder of thecatheter, is single use and disposable. In another embodiment, thechamber is reusable, in which case the luer fitting is positioned inbetween the catheter shaft and the chamber. The heating block isdesigned to be axially aligned with the heating chamber when in use, isreusable, and will not be damaged in the event that it falls to thefloor. In one embodiment, the weight and dimensions of the heating blockare designed such that it can be integrated into a pen-sized and shapedhandle of the ablation catheter. The handle is thermally insulated toprevent injury to the operator.

In one embodiment, the heating block receives its power from a consolewhich is itself line powered and designed to provide 700-1000 W ofpower, as determined by the fluid vaporization rate. The heating blockand all output connections are electrically isolated from line voltage.In one embodiment, the console includes a user interface allowingadjustment of power with a commensurate fluid flow rate. In addition, inone embodiment, a pump, such as a syringe pump, is used to control theflow of fluid to the heating chamber and heating element. In oneembodiment, the volume of the syringe is at least 10 ml and is ideally60 ml.

In the above embodiment, the catheter to be used with the vapor ablationsystem is designed using materials intended to minimize cost. In oneembodiment, the tubing used with the catheter is able to withstand atemperature of at least 125° C. and can flex through an endoscope's bendradius (approximately 1 inch) without collapse. In one embodiment, thesection of the catheter that passes through an endoscope is 7 French(2.3 mm) diameter and has a minimum length of 215 cm. In one embodiment,thermal resistance is provided by the catheter shaft material whichshields the endoscope from the super-heated vapor temperature. In oneembodiment, the heat exchange unit is designed to interface directlywith, or in very close proximity to, an endoscope's biopsy channel tominimize the likelihood of a physician handling heated components.Having the heat exchange unit in close proximity to the endoscope handlealso minimizes the length of the catheter through which the vapor needsto travel, thus minimizing heat loss and premature condensation.

In various embodiments, other means are used to heat the fluid withinthe catheter fluid heating chamber. FIG. 32A illustrates the use ofinduction heating to heat a chamber 3205. When an alternating electriccurrent 3202 is passed through a coil 3207 of wire within the chamber3205, the coil 3207 creates a magnetic field 3209. Magnetic lines offlux 3210 of the magnetic field 3209 cut through the air around the coil3207. When the chamber 3205 is composed of a ferrous material, such as,iron, stainless steel, or copper, electrical currents known as eddycurrents 3215 are induced to flow in the chamber 3205 as a result of thepresence of the alternating current 3202 and magnetic field 3209 withlines of flux 3210. The eddy currents 3215 cause localized heating ofthe chamber 3205. When the chamber 3205 is filled with a fluid, such aswater, the heat is transferred from the chamber to the fluid inside,resulting in vaporization of said fluid. In the embodiment depicted inFIG. 32A, the coil 3207 is looped about the chamber 3205 with four loopsand spaced a distance away from said chamber 3205 to assist withvisualization. The design of the chamber and coil in FIG. 32A depictsonly one possible embodiment and is not intended to be limiting. Thoseskilled in the art will understand many different design configurationsare possible with respect to the chamber and coil. In variousembodiments, the coil includes at least one loop about the chamber andis looped about said chamber such that the coil is in physical contactwith said chamber. In other embodiments, the coil includes at least oneloop about the chamber and is looped about said chamber such that thecoil is spaced away a specific distance from said chamber with a layerof air or other insulating material between said coil and said chamber.In various embodiments, the loops of the coil are arranged closelytogether such that they are in contact with one another. In otherembodiments, the loops of the coil are arranged with a specific distancebetween one another. In one embodiment, the loops of the coil extendalong the entire length of the chamber. In various embodiments, theloops of the coil extend beyond the length of the chamber. In otherembodiments, the loops of the coil extend along a portion of the lengthof the chamber that is less than the chamber's total length.

FIG. 32B is a flow chart listing the steps involved in using inductionheating to heat a chamber. At step 3252, a metal coil is placed about achamber composed of a ferromagnetic material such that the coilsurrounds the chamber. Then, at step 3254, the chamber is filled with afluid via a proximal inlet port on said chamber. At step 3256, analternating current is provided to the coil, creating a magnetic fieldin the area surrounding the chamber. The magnetic field induces electric(eddy) current flow in the ferromagnetic material which heats thechamber. The heat is transferred to the fluid inside the chamber andvaporizes the fluid. The vaporized fluid exits the chamber via thedistal outlet port.

FIG. 33A illustrates one embodiment of a coil 3370 used with inductionheating in the vapor ablation system of the present specification. Asection of the coil 3370 has been cut away to assist with visualization.The coil 3370 is positioned surrounding the catheter fluid heatingchamber 3351. An alternating current 3302 passing through the coil 3370creates a magnetic field which induces eddy currents 3315 to flow in thechamber 3370 as described above. The flow of eddy currents 3315 resultsin heating of the catheter fluid heating chamber 3351. The heatedchamber heats the fluid within, converting it into a vapor, which passesinto the catheter 3350 for use in the ablation procedure. The coil 3370itself does not heat, making it safe to touch. A luer fitting coupler3349 is provided at the proximal end of the catheter fluid heatingchamber 3351 for connecting a tube supplying sterile water. In oneembodiment, a one-way valve (not shown) is included at the proximal endof the catheter fluid heating chamber 3351, distal to the luer fitting3349, to prevent the passage of vapor toward the water supply. In oneembodiment, thermal insulating material (not shown) is positionedbetween the coil 3370 and the heating chamber 3351. In anotherembodiment, the chamber 3351 is suspended in the center of the coil 3370with no physical contact between the two. In this embodiment, theintervening air acts as a thermally insulating material. The design ofthe chamber is optimized to increase its surface area to maximizecontact and heat transfer, in turn resulting in more efficient vaporgeneration. In one embodiment, the coil 3370 is constructed in a‘clamshell’ style design, similar to the heat exchange unit 3160depicted in FIG. 31A, and opens and closes about the heating chamber3351. In another embodiment, the coil 3370 is constructed in a closedstyle design, similar to the heat exchange unit 3170 depicted in FIG.31B, and slides over the heating chamber 3351.

In various embodiments, the induction heating systems and structuresdescribed in FIGS. 32A and 33A can be applied to any of the fluidchambers shown in any of the disclosed embodiments of the presentspecification.

FIG. 33B illustrates one embodiment of a catheter handle 3372 used withinduction heating in the vapor ablation system of the presentspecification. The handle 3372 is thermally insulated and incorporatesan induction coil. In one embodiment, the handle 3372 includes aninsulated tip 3373 at its distal end that engages with an endoscopechannel after the catheter is inserted into the endoscope. The catheter3350 is connected to the heating chamber 3351 which in turn is connectedwith the pump via an insulated connector 3374. In one embodiment, theheating chamber 3351 length and diameter are less than those of thehandle 3372 and the induction coil, thus the heating chamber 3351 canslide inside the handle 3372 in a coaxial fashion while maintaining aconstant position within the magnetic field generated by the inductioncoil. The operator can manipulate the catheter 3350 by grasping on theinsulated connector 3374 and moving it in and out of the handle 3372which in turn moves the catheter tip in and out of the distal end of theendoscope. In this design, the heated portions of the catheter 3350 arewithin the channel of the endoscope and in the insulated handle 3372,thus not coming into contact with the operator at anytime during theoperation. An optional sensor 3375 on the insulated tip 3373 can sensewhen the catheter is not engaged with the endoscope and temporarilydisable the heating function of the catheter to prevent accidentalactivation and thermal injury to the operator. With respect to FIG. 33B,the catheter 3350 and heating chamber 3351 are the heated components ofthe system while the handle 3372, insulated tip 3373, and insulatedconnector 3374 are the cool components and therefore safe to touch bythe user.

FIGS. 34A and 34B are front and longitudinal view cross sectionaldiagrams respectively, illustrating one embodiment of a catheter 3480used with induction heating in the vapor ablation system of the presentspecification. The catheter 3480 includes an insulated handle 3486 thatcontains a heating chamber 3451 and an induction coil 3484. The heatingchamber 3451 includes a luer lock 3449 at its proximal end. The luerlock 3449 has a one-way valve that prevents the backward flow of vaporfrom the chamber 3451. Vaporization of fluid in the chamber results involume expansion and an increase in pressure which pushes the vapor outof the chamber 3449 and into the catheter body. The induction coil 3484includes a wire 3486 that extends from the proximal end of the catheter3480 for the delivery of an alternating current. The handle 3486 isconnected to the catheter 3480 with an outer insulating sheath 3481 madeof a thermally insulating material.

In various embodiments, the insulating material is polyether etherketone (PEEK), polytetrafluoroethylene (PTFE), fluorinated ethylenepropylene (FEP), polyether block amide (PEBA), polyimide, or a similarmaterial. In various embodiments, optional sensors 3487 positionedproximate the distal end of the catheter 3480 measure one or more oftemperature, pressure, or flow of vapor and transmit the information toa microprocessor, which in turn controls the flow rate of the fluid andthe level of vaporizing energy provided to the chamber 3451. Themicrocontroller adjusts fluid flow rate and chamber temperature based onthe sensed information, thereby controlling the flow of vapor and inturn, the flow of ablative energy to the target tissue.

In one embodiment, the catheter 3480 includes an inner flexible metalskeleton 3483. In various embodiments, the skeleton 3483 is composed ofcopper, stainless steel, or another ferric material. The skeleton 3483is in thermal contact with the heating chamber 3451 so that the heatfrom the chamber 3451 is passively conducted through the metal skeleton3483 to heat the inside of the catheter 3480, thus maintaining the steamin a vaporized state and at a relatively constant temperature. Invarious embodiments, the skeleton 3483 extends through a particularportion or the entire length of the catheter 3480. In one embodiment,the skeleton 3483 includes fins 3482 at regular intervals that keep theskeleton 3483 in the center of the catheter 3480 for uniform heating ofthe catheter lumen.

In another embodiment, as seen in FIG. 34C, the catheter includes aninner metal spiral 3488 in place of the skeleton. In yet anotherembodiment, as seen in FIG. 34D, the catheter includes an inner metalmesh 3489 in place of the skeleton. Referring to FIGS. 34B, 34C, and 34Dsimultaneously, water 3432 enters the luer lock 3449 at a predeterminedrate. It is converted to vapor 3438 in the heating chamber 3451. Themetal skeleton 3483, spiral 3488, and mesh 3489 all conduct heat fromthe heating chamber 3451 into the catheter lumen to prevent condensationof the vapor in the catheter and insure that ablating vapor will exitthe catheter from one or more holes or ports at its distal end.

FIG. 35 illustrates one embodiment of a heating unit 3590 usingmicrowaves 3591 to convert fluid to vapor in the vapor ablation systemof the present specification. The microwaves 3591 are directed towardthe catheter fluid heating chamber 3551, heating the chamber 3551 andconverting the fluid within into vapor. The vapor passes into thecatheter 3550 for use in the ablation procedure. A luer fitting coupler3549 is provided at the proximal end of the catheter fluid heatingchamber 3551 for connecting a tube supplying sterile water. In oneembodiment, a one-way valve (not shown) is included at the proximal endof the catheter fluid heating chamber 3551, distal to the luer fitting3549, to prevent the passage of vapor toward the water supply.

In various embodiments, other energy sources, such as, High IntensityFocused Ultrasound (HIFU) and infrared energy, are used to heat thefluid in the catheter fluid heating chamber.

FIG. 36A is illustrates a catheter assembly having an inline chamber3610 for heat transfer in accordance with one embodiment of the presentspecification and FIG. 36B illustrates the catheter assembly of FIG. 36Aincluding an optional handle 3630. Referring to FIGS. 36A and 36Bsimultaneously, the assembly includes a catheter 3605 having an elongatebody with a lumen within, a proximal end, and a distal end. A firstinline chamber 3610, having an elongate body with a lumen within, aproximal end and a distal end, is attached at its distal end to theproximal end of the catheter 3605. In various embodiments, the firstinline chamber 3610 is composed of a ferromagnetic substance or athermally conducting substance. The lumen of the catheter 3605 is influid communication with the lumen of the first inline chamber 3610. Asecond inline chamber 3620, having an elongate body with a lumen within,a proximal end and a distal end, is attached at its distal end to theproximal end of the first inline chamber 3610. The second inline chamber3620 is filled with a fluid. The lumen of the first inline chamber 3610is in fluid communication with the lumen of the second inline chamber3620. In one embodiment, the connection between the first inline chamber3610 and the second inline chamber 3620 includes an optional valve 3615to control the flow of fluid from said second inline chamber 3620 tosaid first inline chamber 3610.

The catheter assembly is connected to a pump which controls the flow offluid from said second inline chamber 3620 to said first inline chamber3610. In one embodiment, the pump is a syringe pump that engages apiston 3625 within and proximate the proximal end of the second inlinechamber 3620 which pushes the fluid from said second inline chamber 3620into said first inline chamber 3610 at a predefined rate. In oneembodiment, the pump is controlled by a microprocessor. In oneembodiment, the microprocessor receives optional information fromsensors in the catheter or in the tissue to control the flow of thefluid from chamber 3620 into chamber 3610. In various embodiments, thefluid is heated in chamber 3610 using any conventional methods ofheating, including those discussed above. In various embodiments, thefirst inline chamber 3610 has more than one channel for the flow of thefluid to increase the surface area of contact of the fluid with thechamber 3610 surfaces, improving the efficiency of heating the fluid. Inone embodiment, the first inline chamber 3610 is optionally covered by amaterial that is a poor thermal conductor, preventing the escape of heatfrom the chamber 3610. This embodiment is preferred if the method ofheating is electromagnetic induction. In one embodiment, referring toFIG. 36B, the catheter 3605 includes an optional handle 3630 allowingfor safe maneuvering of the catheter assembly. In one embodiment, thehandle 3630 is composed of a material that is a poor thermal conductorto prevent thermal injury to the operator from over-heating of thecatheter 3605.

It is desirable to have an integrated system as it eliminates anyconnections that may malfunction or leak causing system malfunctionand/or injury to a patient or an operator. Additionally, it is desirableto have the fluid and heating chambers included as parts of the catheterassembly which eliminates problems encountered with corrosion of themetal in the heating chamber with multiple uses and also ensuressterility of the ablation fluid with multiple uses.

FIG. 36C illustrates the catheter assembly of FIG. 36B connected to agenerator 3640 having a heating element 3650 and a pump 3645, inaccordance with one embodiment of the present specification. Thecatheter connects to the generator 3640 with the heating element 3650and pump 3645. In various embodiments, the heating element 3650 is aresistive heater, an RF heater, a microwave heater, or anelectromagnetic heater. The piston 3625 engages with the pump 3645. Oninitiating therapy, the pump 3645 pushes on the piston 3625 to deliverfluid from the second inline chamber 3620 into the first inline chamber3610 through valve 3615 at a predetermined rate. In one embodiment, thefluid is water. The water is heated in the first inline chamber 3610 tobe converted into vapor. As the vapor expands it is pushed out throughthe distal end of the catheter 3605 to be delivered to the desiredtissue for ablation. In the pictured embodiment, the catheter assemblyincludes a handle 3630 for manipulating the catheter 3605 which has beenfilled with heated water vapor.

As stated above, it is desirable to have a large surface area within theheating chamber for contact heating of the ablative agent. This isaccomplished by having multiple small channels within the heatingchamber. In various embodiments, the channels are created by packing thechamber with metal tubes, metal beads, or metal filings, all of whichsignificantly increase the surface area for contact heating. FIG. 37Aillustrates a heating chamber 3705 packed with metal tubes 3707 inaccordance with one embodiment of the present specification. FIG. 37Billustrates a heating chamber 3715 packed with metal beads 3717 inaccordance with one embodiment of the present specification. FIG. 37Cillustrates a heating chamber 3725 packed with metal filings 3727 inaccordance with one embodiment of the present specification. In variousembodiments, the heating chamber 3705, 3715, 3725 and its channels 3707,3717, 3727 are made of a ferromagnetic material or a thermallyconducting material and the ablative agent 3708, 3718, 3728 flowsthrough these channels 3707, 3717, 3727 where it is heated rapidly andin an efficient manner.

In one embodiment, the heat chamber and its channels are made of amaterial having a specific Curie point or Curie temperature (T_(c)).These materials undergo a phase change from ferromagnetic toparamagnetic when subjected to their T_(c). If such a material is insidean electromagnet that is driven with AC power of several kHz, thematerial exhibits large magnetic hysteresis losses and is ferromagneticbelow T_(c), which results in Joule heating. At T_(c), the materialabruptly loses its soft magnetic property, its magnetic hysteresisvanishes and the Joule heating is reduced by several orders ofmagnitude. As the material cools below T_(c), the hysteresis lossesincrease again, heating resumes and the cycle is repeated.

This physical phenomenon is used to develop a heating device with anintrinsic “thermostat”. In essence, such an element absorbs the energyfrom the electromagnetic field precisely as needed to maintain itstemperature at T_(c) but will not heat above it, making it inherentlyfailsafe from overheating. Moreover, areas of the device that are cooleddue to heat transfer to the surrounding tissue immediately reheat whileareas where heat has not been transferred to the tissue cease heating.

T_(c) can easily be adjusted by selecting the ratios of low-cost basemetals in the material. Industry standard soft magnetic nickel-ironalloys containing from about 28% to 70% nickel (Ni) have Curietemperatures ranging from room temperature to 600° C. For targettemperatures of 100° C.-120° C., the class of low-nickel alloyscontaining 30% Ni are most suitable. For higher temperatures, higher Niconcentrations are desirable. Small additions of copper (Cu), silicon(Si), manganese (Mn), or chromium (Cr) allow for alloying of veryprecise Curie temperatures. For example, several low Curie temperatureiron-chromium-nickel-manganese (Fe—Cr—Ni—Mn) alloys are listed in Table3 below.

TABLE 3 Chemical Composition [wt. %] T_(c) [° C.] Cr4Ni32Fe62Mn1.5Si0.555 Cr4Ni33Fe62.5Si0.5 120 Cr10Ni33Fe53.5Mn3Si0.5 10 Cr11Ni35Fe53.5Si0.566

In order to have high insulation properties, the catheters describedabove require increased wall thickness. The increased wall thicknesswould decrease the size of the lumen and increase the resistance to flowof the ablative agent. Therefore, in various embodiments, the innersurface of the catheter includes a groove to decrease the resistance toflow of an ablative agent. FIG. 38A illustrates a cross-sectional viewof one embodiment of a catheter 3805 having an internal groove 3810 todecrease flow resistance and FIG. 38B illustrates an on-end view of oneembodiment of a catheter 3815 having an internal groove 3820 to decreaseflow resistance.

In another embodiment, the resistance to flow is reduced by sending asound wave down the catheter bore along with the ablative agent tocreate sympathetic resonances. The sympathetic resonances create achanneling effect where friction with the vessel wall is dramaticallyreduced.

To improve the thermal insulation property of the catheter, a duallayered catheter can be formed with a thin layer of air or insulatingfluid between the two catheter layers. In one embodiment, the insulatinglayer of air or fluid is circulated back into the power generator tofacilitate heat transfer into the generator rather than through thecatheter walls. FIG. 39A illustrates a cross-sectional view of a doublelayered catheter in accordance with one embodiment of the presentspecification. The catheter includes an inner wall 3905 and an outerwall 3915 separated by a thin layer 3910 of air or insulating fluid. Thetwo walls 3905, 3910 are connected at their proximal and distal ends(not shown). FIG. 39B illustrates a cross-sectional view of a doublelayered catheter in accordance with another embodiment of the presentspecification. The catheter includes an inner wall 3925 and an outerwall 3935. The two walls 3925, 3935 are connected at their proximal anddistal ends (not shown) and are connected at intervals by spokes 3940which provide additional support. Multiple air or fluid filled channels3930 are positioned between the two walls 3925, 3935. In one embodiment,the inner and outer walls (and spokes shown in FIG. 39B) are composed ofpolyether ether ketone (PEEK).

One advantage of a vapor delivery system utilizing a heating coil isthat the vapor is generated closer to the point of use. Traditionalvapor delivery systems often generate vapor close to or at the point inthe system where the liquid is stored. The vapor must then travelthrough a longer length of tubing, sometimes over 2 meters, beforereaching the point of use. As a result of the distance traveled, thesystem can sometimes deliver hot liquid as the vapor cools in the tubingfrom the ambient temperature.

The devices and methods of the present specification can be used tocause controlled focal or circumferential ablation of targeted tissue tovarying depth in a manner in which complete healing withre-epithelialization can occur. Additionally, the vapor could be used totreat/ablate benign and malignant tissue growths resulting indestruction, liquefaction and absorption of the ablated tissue. The doseand manner of treatment can be adjusted based on the type of tissue andthe depth of ablation needed. The ablation device can be used not onlyfor the treatment of Barrett's esophagus and esophageal dysplasia, flatcolon polyps, gastrointestinal bleeding lesions, endometrial ablation,pulmonary ablation, but also for the treatment of any mucosal,submucosal or circumferential lesion, such as inflammatory lesions,tumors, polyps and vascular lesions. The ablation device can also beused for the treatment of focal or circumferential mucosal or submucosallesions of any hollow organ or hollow body passage in the body. Thehollow organ can be one of gastrointestinal tract, pancreaticobiliarytract, genitourinary tract, respiratory tract or a vascular structuresuch as blood vessels. The ablation device can be placed endoscopically,radiologically, surgically or under direct visualization. In variousembodiments, wireless endoscopes or single fiber endoscopes can beincorporated as a part of the device. In another embodiment, magnetic orstereotactic navigation can be used to navigate the catheter to thedesired location. Radio-opaque or sonolucent material can beincorporated into the body of the catheter for radiologicallocalization. Ferro- or ferrimagnetic materials can be incorporated intothe catheter to help with magnetic navigation.

The above examples are merely illustrative of the many applications ofthe system of the present invention. Although only a few embodiments ofthe present invention have been described herein, it should beunderstood that the present invention might be embodied in many otherspecific forms without departing from the spirit or scope of theinvention. Therefore, the present examples and embodiments are to beconsidered as illustrative and not restrictive, and the invention may bemodified within the scope of the appended claims.

We claim:
 1. A method of ablating endometrial tissue comprising thesteps of: providing an ablation device comprising: a catheter having ahollow shaft through which an ablative agent can travel; a firstpositioning element attached to said catheter; a second positioningelement attached to said catheter and positioned on said catheter distalto said first positioning element, wherein said second positioningelement is a balloon; at least one infusion port on said catheter fordelivery of said ablative agent to said endometrial tissue; and acontroller comprising a microprocessor for controlling the delivery ofsaid ablative agent; inserting said catheter through a cervix and into auterus of a patient such that said first positioning element ispositioned in said cervix and said second positioning element ispositioned proximate a fundus or body of said uterus; deploying saidfirst and second positioning elements such that said first positioningelement contacts said cervix, said second positioning element contacts aportion of said uterus proximate said fundus or body, and said catheterand at least one infusion port are positioned within a uterine cavity ofsaid patient; and delivering said ablative agent through said at leastone infusion port to ablate said endometrial tissue.
 2. The method ofclaim 1, wherein said ablation device further comprises at least onesensor for measuring at least one dimension of said uterine cavity andsaid method further comprises the steps of: operating said at least onesensor to measure said at least one dimension of said uterine cavity;and using said at least one dimension of said uterine cavity todetermine an amount of said ablative agent to deliver to saidendometrial tissue.
 3. The method of claim 2, wherein said at least onesensor comprises an infrared, electromagnetic, acoustic, orradiofrequency energy emitter and sensor.
 4. The method of claim 1,wherein said first positioning element is cone shaped and, oncedeployed, positions said catheter in a center of said cervix andoccludes a cervical opening.
 5. The method of claim 1, wherein saidfirst positioning element is oval shaped, having a length in a range of0.1 mm to 10 cm and a width in a range of 0.1 mm to 5 cm and, oncedeployed, positions said catheter in a center of said cervix andoccludes a cervical opening.
 6. The method of claim 4, wherein saidfirst positioning element is covered by an insulated membrane forpreventing an escape of said ablative agent through said cervix andbeyond said uterine cavity.
 7. The method of claim 6, wherein a segmentof said catheter includes a predetermined length and said methodincludes the steps of: using said predetermined length and/or a diameterof said second positioning element to estimate a size of said uterinecavity; and using said estimated size of said uterine cavity tocalculate an amount of thermal energy of said ablative agent required toablate said endometrial tissue.
 8. The method of claim 1, wherein saidfirst and second positioning elements are separated from endometrialtissue to be ablated by a distance of greater than 1 mm.
 9. The methodof claim 1, wherein said first and second positioning elements arewithin an area including endometrial tissue to be ablated.
 10. Themethod of claim 1, wherein said delivering of said ablative agent isguided by predetermined programmatic instructions.
 11. The method ofclaim 1, wherein said ablation device further comprises at least onesensor for measuring a parameter of said uterus and said method furthercomprises the steps of: operating said at least one sensor to measuresaid parameter of said uterus; and using the measure of said parameterto increase or decrease a flow of said ablative agent to saidendometrial tissue.
 12. The method of claim 11, wherein said at leastone sensor is any one of a temperature, pressure, photo, or chemicalsensor.
 13. The method of claim 1, wherein said ablation device furthercomprises a coaxial member configured to restrain said first and secondpositioning elements and said step of deploying said first and secondpositioning elements further comprises withdrawing said coaxial memberover said ablation device.
 14. The method of claim 1, wherein saidablation device further comprises an input device and said methodfurther comprises using said input device to control the delivery ofsaid ablative agent.
 15. The method of claim 1, wherein said ablationdevice further comprises at least one input port on said catheter forreceiving said ablative agent.
 16. A method of ablating endometrialtissue comprising the steps of: providing an ablation device comprising:a catheter having a hollow shaft through which an ablative agent cantravel; a first positioning element attached to said catheter; a secondpositioning element attached to said catheter and positioned on saidcatheter distal to said first positioning element, wherein said secondpositioning element is a balloon; at least one infusion port on saidcatheter for delivery of said ablative agent to said endometrial tissue;at least one mechanism for measuring at least one dimension of a uterinecavity; and a controller comprising a microprocessor for controlling thedelivery of said ablative agent; inserting said catheter through acervix and into a uterus of a patient such that said first positioningelement is positioned in said cervix and said second positioning elementis positioned in the uterine cavity; deploying said first and secondpositioning elements such that said first positioning element contactssaid cervix, said second positioning element contacts a portion of saiduterus within said uterine cavity, and said catheter and at least oneinfusion port are positioned within said uterine cavity of said patient;operating said at least one mechanism to measure at least one dimensionof said uterine cavity; using said at least one dimension measurement todetermine an amount of ablative agent to deliver to said endometrialtissue; and delivering said ablative agent through said at least oneinfusion port to ablate said endometrial tissue.